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Puff pastry is the backbone of this tart. Its flaky layers create a delightful texture that contrasts beautifully with the creamy filling. When baked, puff pastry puffs up and forms air pockets, resulting in a light and airy crust that is both crispy and tender.

Caramelized Onion & Gruyère Tart – Elegant & Delicious!

Discover the deliciousness of Caramelized Onion & Gruyère Tart, where sweet caramelized onions meet rich Gruyère cheese in a flaky puff pastry crust. Perfect for brunch, dinner parties, or cozy nights at home, this French-inspired dish will elevate your culinary repertoire. With tips on selecting ingredients, caramelizing onions, and achieving the ideal crust, you'll impress your guests and indulge your taste buds with this savory treat. Ideal for any occasion, it’s time to bring this culinary delight to your table!
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Ingredients
  

1 sheet of puff pastry (thawed if frozen)

3 large onions (yellow or sweet), thinly sliced

2 tablespoons unsalted butter

1 tablespoon olive oil

1 teaspoon sugar

Salt and freshly ground black pepper, to taste

1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme)

1 cup Gruyère cheese, grated

2 large eggs

1 cup heavy cream

1 tablespoon Dijon mustard

Fresh herbs (for garnish, optional)

Instructions
 

Preheat the Oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

    Prepare the Puff Pastry: Roll out the puff pastry on a lightly floured surface to fit your tart pan. Place the rolled pastry into a 9-inch tart pan, pressing gently to fit. Trim any excess pastry, and prick the base with a fork to prevent it from puffing during baking. Chill in the fridge while you prepare the filling.

      Caramelize the Onions: In a large skillet over medium heat, melt the butter and olive oil together. Add the sliced onions, a pinch of salt, and sugar. Cook the onions slowly, stirring occasionally, until they are golden brown and caramelized (about 20-25 minutes). Add the thyme during the last few minutes of cooking. Remove from heat and let cool slightly.

        Mix the Custard: In a mixing bowl, whisk together the eggs, heavy cream, Dijon mustard, and season with salt and pepper.

          Assemble the Tart: Spread the caramelized onions evenly over the bottom of the chilled pastry shell. Sprinkle the grated Gruyère cheese over the onions. Pour the egg and cream mixture over the cheese evenly.

            Bake: Place the tart in the preheated oven and bake for 25-30 minutes, or until the filling is set and the top is golden brown.

              Cool & Serve: Allow the tart to cool slightly before slicing. Garnish with fresh herbs if desired. Serve warm or at room temperature.

                Prep Time: 15 minutes | Total Time: 1 hour | Servings: 6-8 servings