Caramelized Onion, Mushroom & Gruyere Tartlets
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.
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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
Ingredients
- 1 tablespoon olive oil
- 1 large yellow onion, thinly sliced
- 1 tablespoon unsalted butter
- 16 ounces (453.59 g) white button mushrooms, thinly sliced
- 1 clove garlic, chopped
- ½ teaspoon (0.5 teaspoon) dried thyme
- Salt and pepper, to taste
- ¼ cup (60 ml) white wine, can substitute chicken or vegetable broth
- 2 sheets puff pastry, thawed according to directions on package
- 1 cup (132 g) shredded Gruyere cheese, can substitute any variety of Swiss cheese
- 1 egg + 1 tablespoon water, beaten together (for the egg wash)
- Handful of parsley, chopped
Instructions
- Preheat oven to 400 degrees F and line two baking sheets with parchment paper.
- 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.
- 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.
- Add the garlic and the thyme and saute until fragrant, about 1 minute. Season with salt and pepper to taste.
- 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.
- 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.
- 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.
- Bake until the pastry is golden brown, about 15 to 25 minutes. Garnish with fresh chopped parsley.
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I have made these multiple times – they are amazing! Wondering if there’s a shortcut to speed up the recipe. I would love to make them for an upcoming event, but I don’t have enough time during the week. Any suggestions?
Hi Michelle, You could do each component ahead of time – make the caramelized onion filling ahead of time, cool and store in the refrigerator for up to 2 days. You can also cut out the puff pastry rounds up to a few days ahead, as well – just place them on a parchment-lined sheet and refrigerate. Then assemble when you’re ready! I wouldn’t store the assembled tarts in the refrigerator for too long, as I’d be afraid that the cooked vegetables could make the pastry soggy.
I have made these twice as a main dish for thanksgiving. Here are my tips:
1. Make mushroom-onion filling the day before. Put frozen pastry in fridge to defrost overnight.
2. I used a large, mason-jar lid as cutter. Then, I used a smaller glass to make the inner perimeter circle. This saves time, as scoring takes too long.
3. Brush the eggwash on the pastry circles before you place the filling on top of each one, its faster and easier.
4. I cooked them earlier in the day, for 15 minutes, left them at room temp., then reheated for five to eight minutes just before serving. They were just as good.
5. I doubled the recipe for 13 people, as the main dish, and made them larger. Leftovers the next day, heated up were delicious.
6. All six children at our party liked them.
7. Next time, I will use sherry instead of wine.
8. I use puff pastry that includes 100% butter. I don’t know if the other types are as rich tasting and good.
I aim to make these often. As a holiday dish for vegetarians, they are elegant and delicious.
I am attending an apple picking party this weekend. This going to be my dish to bring. Thanks, it looks lovely.
Can these be prepared and frozen before baking?
Hi Kristyn, I have not tried freezing them, but I think that should work.
I just found your recipe and plan to double this to serve at a party. I’d like to know how much – if any – can I prep the day before?
Thanks!
Hi Dorothy, You could prepare the filling the day before. Enjoy!
Can these be made in advance?
Yes!
Just made these for a holiday party. Amazing!!!! Puff pastry makes everything taste good!
Can you make these ahead and freeze by any chance?
Hi Karen, I think freezing ahead would work.
I made these last Thanksgiving for my vegetarian guests but everyone loved them. Have made them again and each time the recipe yields delicious results. Taking them tomorrow to a pot luck and planning to cook the onions and mushrooms the day before (so I don’t smell like onion at the event). Sounds like from the comments that as long as I assemble and bake just before I leave they should be fine. If anyone has tips for doing this in two stages, would love to hear. Again, great recipe for any level of cook/chef.
Can you use the mini puff pastry cups?
Sure! It will make a lot more than these larger tarts.
I’ve made these for three different parties this year, and they’re fabulous! The only change I made is to increase the onions by using two onions instead of one and decreasing the mushrooms to about 12 oz. or so — to my taste, the mushroom-to-onion ratio is too high as written. Other than that, they’re a great appetizer to have at a party!
Will be making these for sure. Looks incredible!! :)
So this Thanksgiving our meat eaters have their “main” and four the three veggies in the house I wanted something different and yet something special…found it…this will be our “main”
Looks amazing :)
Love your site
Made these today and they turned out beautifully. You are absolutely right that they’re simple yet sophisticated. Thank you for a fabulous recipe — I’m going to make a batch for Thanksgiving!
Do you think these would be ok if they are baked and served at room temp the same day? I am giving a baby shower at a facility that does not have an oven so I would like to bake them at home and bring them with me but they will not warm when served.
Hi Julie, I think they would be okay at room temperature, but I would bake them as late as possible, they really are best when they’re still warm.
Just tried this — delicious! For an extra kick, I added a few splashes of premium vodka. Turned out really well. Thank you so much for the recipe!
I’d like to avoid cutting out the rounds and simply make one large rectangular tart or two if there is enough filling. Would that work? Any adaptations reccommended? Same amount of phylo? Same baking time? I’d score around the perimeter to get the edges. Please advise Thanks!
Hi Sue, Yes, you could definitely do that. I’d keep the baking time the same. Let me know how it goes!
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!
Hi Kim, I’m not sure how the onions would freeze and re-heat, but otherwise I think that would be fine.
Hi Kim, Did you make and freeze these? Wondering how they turned out? Thank you!
Just made these over the weekend – they were easy & delicious – have already been asked for the recipe 3 times! Thanks for posting!
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!
Oops! I just read the comment above – sorry!. I’m set.
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!
Hi Sara, I would reheat in a 375-degree oven very briefly, to ensure the cheese is melted.
Do you think I could make them the night ahead and reheat the next day in a warming tray?
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.
Hi Racquel, I was wondering if you made them ahead and reheated them and how they turned out? Thankyou!
I’m dying to know too. I’d like to make these tonight or a few hours before the party I’m attending, I don’t want to bother the host with having to bake something while she’s entertaining… should I cook them fully and reheat at the party, or partially cook them at home and finish cooking at the party?
Thanks! They look amazing!
Do you roll out the pastry with a rolling pin or just cut it once it has thawed?
Thanks!
No need to roll, just unfold the sheets and then cut.
These look soooo good, but I hate. Hate. HATE. mushrooms. Apples instead, perhaps?
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.
I love the idea of the cookbook as a keepsake!
These tarts look amazing! I can’t wait to try this recipe!
I love the idea of a virtual shower, with the guests “bringing” food! (And, by the way, the tartlets look delicious.)
These are just gorgeous and I love the flavor combo!!!
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.
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!
Have been using Babette’s sizing recommendations for 3 different events.
The 2” cutter with a 1 1/2” cutter to score is perfect
Each sheet of Dufour puff pastry is the size of legal paper, 8 1/2 x 14”. My yield has been 18 tartlets per sheet.
This wonderful recipe is simple with a lovely depth of flavor. A crowd pleaser. Thank you!
I don’t enjoy eating onions except having them in soups. But these caramelised onion tartlets looked really delicious.