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French Onion Mushroom Tart

French Onion Mushroom Tart


  • Author: Adeline
  • Total Time: 50 minutes
  • Yield: Serves 8

Description

Indulge in the rich flavors of a French Onion Mushroom Tart, an exquisite dish that combines caramelized onions and sautéed mushrooms atop a flaky puff pastry crust. This delightful tart serves as a versatile option for any gathering, whether as a stunning appetizer or a satisfying main course. Its layers of savory goodness and impressive presentation make it a crowd favorite, sure to impress even the most discerning palates.


Ingredients

Scale
  • 1 sheet puff pastry, thawed
  • 2 large onions, thinly sliced
  • 1 1/2 cups mushrooms, sliced (cremini, shiitake, or button mushrooms work well)
  • 2 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 1 teaspoon sugar
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1/2 teaspoon fresh thyme leaves (optional)
  • 1/2 cup Gruyère cheese, grated
  • 1/4 cup Parmesan cheese, grated
  • 1 egg, beaten (for egg wash)

Instructions

  1. Caramelize the onions: In a large skillet, heat butter and olive oil over medium-low heat. Add sliced onions and cook for about 30 minutes until golden brown, stirring occasionally. Season with sugar, salt, and pepper halfway through.
  2. Sauté the mushrooms: In the same skillet on medium heat, add more butter if needed and sauté sliced mushrooms until golden brown and liquid evaporates (about 10 minutes). Stir in thyme if using.
  3. Prepare puff pastry: Preheat oven to 400°F (200°C). Roll out puff pastry into a rectangle to fit your baking sheet lined with parchment paper. Score a 1-inch border around edges.
  4. Assemble the tart: Spread caramelized onions over puff pastry within the border. Top with sautéed mushrooms and sprinkle with Gruyère and Parmesan cheese. Brush edges with beaten egg.
  5. Bake: Bake for 20–25 minutes until pastry is puffed and golden brown with melted cheese.
  • Prep Time: 15 minutes
  • Cook Time: 35 minutes
  • Category: Main Course
  • Method: Baking
  • Cuisine: French

Nutrition

  • Serving Size: 1 slice (117g)
  • Calories: 250
  • Sugar: 3g
  • Sodium: 360mg
  • Fat: 16g
  • Saturated Fat: 8g
  • Unsaturated Fat: 7g
  • Trans Fat: 0g
  • Carbohydrates: 23g
  • Fiber: 2g
  • Protein: 6g
  • Cholesterol: 40mg

Keywords: Use high-quality cheeses for enhanced flavor. Thinly slice onions for even caramelization. Avoid overcrowding mushrooms while sautéing; cook in batches if necessary. Chill puff pastry before baking to achieve maximum flakiness.