Caramelized onion, mushroom, and gruyere tartlets on a white serving plate.

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!

Overhead image of caramelized onion, mushroom, and gruyere tartlets on a white serving plate.

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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Collage of 2 images of assembling caramelized onion, mushroom, and gruyere tartlets.

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! :)

Side view of caramelized onion, mushroom, and gruyere tartlets on a white serving plate.

One year ago: English Muffins

Caramelized onion, mushroom, and gruyere tartlets on a white serving plate.

Caramelized Onion, Mushroom & Gruyere Tartlets

Yield: 16 3-inch tartlets
Prep Time: 20 minutes
Cook Time: 40 minutes
Total Time: 1 hour
These vegetarian tartlets are perfect to serve as an easy appetizer
4.45 (110 ratings)
Print Pin Rate

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.
Calories: 71kcal, Carbohydrates: 2g, Protein: 3g, Fat: 5g, Saturated Fat: 2g, Cholesterol: 21mg, Sodium: 38mg, Potassium: 113mg, Vitamin A: 140IU, Vitamin C: 1.6mg, Calcium: 87mg, Iron: 0.3mg

Did you make this recipe?

Leave a review below, then snap a picture and tag @thebrowneyedbaker on Instagram so I can see it!

Author: Michelle Lettrich
Course: Appetizer
Cuisine: American