Caramelized Onion, Mushroom & Gruyere Tartlets
86 comments » 
Continuing down the road of appetizers, dips and snack food leading up to the Super Bowl, I give you this somewhat “upscale” game day food. Caramelized onions, mushrooms and Gruyere cheese are baked atop circles of puff pastry for a flaky, savory and delicious appetizer. Another occasion that this appetizer would be great for? A baby shower! Fellow food blogger Annie from Annie’s Eats is expecting her second baby in April (a girl!) and a group of bloggers organized a virtual baby shower to celebrate Annie’s bundle of joy, and of course we all brought food to the party! Since appetizers are my second love behind desserts and this is Super Bowl week, I definitely wanted to go that route, and thought that these little tartlets would be something Annie and other ladies at a shower would certainly enjoy. To see all of the great drinks, appetizers, main dishes and desserts that other bloggers contributed to the virtual shower, head on over to Annie’s and Courtney’s blogs for the roundup. For more on the tartlets, keep reading!
One of the great things about these tartlets is that you can cut the circles smaller or larger depending on how many you want to serve or how truly bite-size you want them to be. I did 3-inch circles, but you can definitely adjust depending on your needs.
These are equal parts sophisticated and easy – the best type of entertaining food in my book. You could even prepare the caramelized onions and mushrooms ahead of time and then assemble and bake right before guests arrive. Perfect for a football game or a baby shower! 
One year ago: English Muffins
Caramelized Onion, Mushroom & Gruyere Tartlets
Yield: 16 3-inch tartlets
Prep Time: 1 hour
Cook Time: 20 minutes
Total Time: 1 hour 20 minutes
Ingredients:
1 tablespoon olive oil
1 large yellow onion, thinly sliced
1 tablespoon unsalted butter
16 ounces white button mushrooms, thinly sliced
1 clove garlic, chopped
½ teaspoon dried thyme
Salt and pepper, to taste
¼ cup white wine (can substitute chicken or vegetable broth)
2 sheets puff pastry (thawed according to directions on package)
1 cup shredded Gruyere cheese (can substitute any variety of Swiss cheese)
1 egg + 1 tablespoon water, beaten together (for the egg wash)
Handful of parsley, choppedDirections:
1. Preheat oven to 400 degrees F and line two baking sheets with parchment paper.
2. Heat the olive oil in a wide, heavy-bottomed pan over medium-low heat and add the onions. Cook, stirring occasionally, until they begin to caramelize, about 20 minutes.
3. Add the butter to the pan. Once melted, add the mushrooms and saute, stirring occasionally, until they are completely soft and all of the liquid evaporates, about 20 minutes.
4. Add the garlic and the thyme and saute until fragrant, about 1 minute. Season with salt and pepper to taste.
5. Add the wine, scraping the bottom of the pan to pull up all of the browned bits, and cook until all of the liquid has evaporated. Remove from heat.
6. Unfold the thawed sheets of puff pastry and cut out circles from the dough, placing them evenly spaced on the baking sheets. Using a very sharp knife, make four small scores around the perimeter of the dough, about ¼ to ½-inch from the edge.
7. Top the rounds of puff pastry with a small spoonful of the onion and mushroom mixture, trying to keep the filling within the score marks. Top with the shredded Gruyere cheese. Brush the edges of the dough rounds with the egg wash.
8. Bake until the pastry is golden brown, about 15 to 25 minutes. Garnish with fresh chopped parsley.
(Recipe adapted from Closet Cooking)
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Oh yum! These look perfect for my Superbowl line up! But I’m sure they would also go great at a baby shower
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Those tartlets look mervelous and soooo appetizing! A great combination.
Cheers,
Rosa
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Those look delicious! They seem so elegant but also something that would keep men happy!
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Caramelized onions and gruyere are two of my FAVORITE ingredients. Bookmarking these!
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These look wonderful! Perfect app. I am starring this one!
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Stunning photos! SU’d!!
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These seem like they’re tailor-made for my mushroom & gruyete-loving husband. I’m printing this and may make them for V-Day!
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All of the food at her virtual shower looked amazing and I’d definitely like to eat these in real life!
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These are pretty much all of my favorite things packed into one recipe. They look so elegant and delicious, and I’ll definitely be trying them soon. Thanks again for participating in the virtual shower!
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yum! These are the type of appetizers you make for the wives of the men watching football! The boys can just have chips.
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I love anything with onions and cheese. These are beautiful. I want to reach right in and pick one up from my computer screen. And I love the fact that it’s a vegetarian option for an appetizer. I am adding these to my growing list of amazing must-do’s from this virtual shower!
Shanon
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YUM! That is all I have to say:)
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I have these saved from Kevin’s blog, too. Pretty much all my ingredients on top of buttery puff pastry. Um, yes please!
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Fabulous! Can’t wait to try these.
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Oh, these look SO good. While reading Courtney’s post, I kept wishing this shower were a non-virtual occasion.
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perfect choice for a shower. they really look fantastic!
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Love these perfect little bites! That combination of mushrooms, caramelized onion and Gruyere is just about my favorite. I’d pass right by the desserts to get to this little appetizer. Great job!
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Wow, Michelle! I’m bookmarking these, possibly for the Superbowl. But, I’m thinking I want to just make them when I can eat all of them instead and not have to share!
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What an elegant and easy appetizer! Those are just beautiful. I might save them for the Valentine’s Day party I’m having with my husband and friends. Thanks!
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You have an award waiting for you: http://bit.ly/fE7iqT
Mateja @Indulging Life
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These look so yummy!!
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These look SO good! I’m compelled to put these on my weekly menu for next week. MUST HAVE THEM FOR MYSELF! Seriously, if I have another baby, I think I need to fly you out so you can make food for my baby shower…
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Mmm, these look so flaky and beautiful, Michelle! A perfect shower appetizer! This shower has been SO much fun and I’m so happy to have been a part of it!
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These look absolutely gorgeous. What a perfect appetizer!
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Whoa, these look amazing! Big problem is that I can eat too many of these!!
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These look absolutely delicious. Love all the ingredients….
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I am unsure what you mean by “four small scores around the diameter of the dough.” Can you elaborate and/or post a picture of this step? Thanks!!
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Michelle on February 2nd, 2011 at 2:21 pm
Hi Carol, Unfortunately I don’t have a photo of it, but I basically make four small semi-circle slits on each side of the dough round. You don’t want to cut the whole way through. I found this post with a photo of scored puff pastry, hopefully that helps!
http://veggieobsession.blogspot.com/2010/03/spinach-pear-and-gorgonzola-tart.html
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Melissa on February 4th, 2011 at 12:56 pm
Thanks for asking & answering this question! I needed to know as well!
PS – I’m making these tonight!!
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Look delicious.. I wish I was eating them now…
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Oh goodness, these are PERFECT for the Super Bowl this weekend. Yum!!
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Michelle, when you say “Using a very sharp knife, make four small scores around the diameter of the dough, about ¼ to ½-inch from the edge” I’m not clear on what you mean. Did you mean “diameter” or “perimeter”? The word “around” is what’s giving me difficulty. The diameter is a straight line right down the middle, so “around” doesn’t seem to fit. If you mean make scores around the perimeter, 1/4 to 1/2″ from the edge, that makes more sense to me. Of course, this could just be me…
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Michelle on February 2nd, 2011 at 2:49 pm
I meant perimeter, I changed it above. Good proof as to why I would have never been a good math major
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Cat on February 2nd, 2011 at 2:50 pm
Thanks, Michelle, for the clarification.
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A perfect blend of ingredients. And anything in puff pastry is good as far as I’m concerned!
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These look tasty! I just gruyere on just about anything!
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I saw these on Annie’s Eats and thought they looked absolutely SCRUMPTIOUS!
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These are absolutely adorable, Michelle! The combination of caramelized onions, mushrooms & gruyere is making me salivate.
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I read about your virtual shower on Cook Like a Champion, and I think it’s awesome! These tarts look to die for!
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Little bites of yumminess! These sound wonderful.
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Yes please! These look so good. I can’t wait to give these a go, despite no Super Bowl, or baby shower, excuse!
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Saw these on Annie’s blog, they look AMAZING! Love the flavor combo. YUM!
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I know these are fabulous! I have a very similar recipe that is truly a favorite. Your version looks fun. Will put these on my too do shopping list. Gotta love puff pastry..and mushrooms…and onions and wine!
Bonnie
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Not much else I can say but “YUM” these look so good!!
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These look great. Can’t wait to try them.
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Amazing looking tarts!
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So simple! Can’t wait to give it a try
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this is my kind of snack, I think I could eat a plateful
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These are very nice. Quite similar to some I had last week in Lyon at Sirha while attending Bocuse d’Or. Your recipe is nice a simple.
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So beautiful and I imagine quite tasty too!
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Your mini tartlets look absolutely delicious. I’d love for your to submit them to Vegolicious, a vegetarian food photo gallery where readers can browse beautiful photos to discover new recipes and wonderful blogs. If you would like to share this recipe with our readers please submit http://www.vegolicious.com/submit a photo along with a link to this post.
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These look wonderful! I want to try these!
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These are SO adorable! And perfect for a classy Super Bowl
Or just an evening when I’m in the mood for some tartlets 
Hehe.
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Great combination of flavors. The pictures really make them look like I could grab one right now!
Jason
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Oh, my, what a beautiful and delicious appetizer! I’ll be trying it soon~
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Mmm…so cute and delicious! I love working with puff pastry — that stuff is so versatile. I think I’ll need to experiment with them again soon. You’ve got me thinkin’!
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I’m drooling looking at these! And they don’t seem that difficult to make. thanks for sharing!
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Where was this recipe yesterday?! lol. Some girlfriends had an appetizer cook-off last night. The ingredient everyone had to use was cheese. I ended up making Endive Stuffed with Goat Cheese and Walnuts (http://cookmarked.com/recipe.aspx?eID=55iPZsyqX7RJqZxEnK8WIZ89LuD3heNHd4pVkl6m8sEe). I got 2nd place, but I bet I would have won with this!
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These look YUMMY! Has anyone made them ahead of time and then re-heated them at an event? I am doing a BIG event next month and need some finger appies that can be preped a day or two ahead of time and then re-heated as I put them out. Wondering if these would work. Let me know if you have tried and if it was a success. Thanks
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Ahh puff pastry. Is there any dish it can’t make better?
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They look absolutely divine! Yum! Thanks for sharing!
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Those tartlets look divine, might have to steal this one for the next house party I throw, this blog saves my behind on so many levels
many thanks
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What a great recipe! Puff pastry is such an effortless way to make a sophisticated dish.
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your tartlets looks so good. love all the ingredients.
thanks for sharing Michelle, hope you’ll have a wonderful Friday
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I don’t enjoy eating onions except having them in soups. But these caramelised onion tartlets looked really delicious.
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I made these for my Super Bowl party. They were a huge hit! I used beef stock instead of wine. I also used two round cookie cutters – a 2 inch to cut the rounds, and a 1 1/2 inch to score the edge, which was a lot faster and more uniform than using a knife. Two thumbs up!
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Thanks for the link to my blog!! These little tarts look fantastic. I want to try them with oyster mushrooms – we have a couple of local farmers who grow them here in Albuquerque, and I’m always looking for something special to do with them.
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These are just gorgeous and I love the flavor combo!!!
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I love the idea of a virtual shower, with the guests “bringing” food! (And, by the way, the tartlets look delicious.)
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These tarts look amazing! I can’t wait to try this recipe!
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These look so good. I love virtual parties. Aren’t they fun? I have taken part in quite a few over the years. It is great to see what types of recipes post for the event. In one of the groups, we put together a cookbook of the recipes from the party and all the participants got one.
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Mary Poppins in Heels on February 24th, 2011 at 9:02 am
I love the idea of the cookbook as a keepsake!
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These look soooo good, but I hate. Hate. HATE. mushrooms. Apples instead, perhaps?
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Do you roll out the pastry with a rolling pin or just cut it once it has thawed?
Thanks!
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Michelle on November 7th, 2012 at 1:08 pm
No need to roll, just unfold the sheets and then cut.
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Hi! I want to make these as an appetizer on Thanksgiving, but will need to make/ drive an hour/ possibly reheat- any suggestions on how to reheat these amazing looking bites?
Thanks!
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Michelle on November 15th, 2012 at 5:52 pm
Hi Sara, I would reheat in a 375-degree oven very briefly, to ensure the cheese is melted.
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Racquel on November 21st, 2012 at 10:45 pm
Do you think I could make them the night ahead and reheat the next day in a warming tray?
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Michelle on November 22nd, 2012 at 8:43 am
Yes, I think that would work, you might want to pop them under the broiler for a quick second just to make sure the cheese isn’t a solid mass and it melts.
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Michelle on April 4th, 2013 at 6:56 pm
Hi Racquel, I was wondering if you made them ahead and reheated them and how they turned out? Thankyou!
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I’m making these for Christmas day. Do you think I can prep the onion & mushroom mixture the night before and assemble before everyone arrives?
Thanks!
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Meghan on December 23rd, 2012 at 11:38 am
Oops! I just read the comment above – sorry!. I’m set.
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Just made these over the weekend – they were easy & delicious – have already been asked for the recipe 3 times! Thanks for posting!
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Can these be made and then frozen (before they are cooked), later thawing and popping into the oven? I need to make some good tartlets in advance for Girls Night. Thanks!
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Michelle on February 19th, 2013 at 8:11 pm
Hi Kim, I’m not sure how the onions would freeze and re-heat, but otherwise I think that would be fine.
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Michelle on April 4th, 2013 at 6:54 pm
Hi Kim, Did you make and freeze these? Wondering how they turned out? Thank you!
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