Description
These Caramelized Onion Tarts are a delightful French-inspired appetizer featuring buttery puff pastry topped with sweet, deeply caramelized onions and melted Gruyère cheese. Perfect for serving warm or at room temperature, they are easy to prepare and sure to impress guests with their rich flavors and golden, flaky crusts.
Ingredients
Scale
Puff Pastry Base
- 1 sheet puff pastry, thawed
Caramelized Onions
- 2 large yellow onions, thinly sliced
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme)
- ½ teaspoon salt
- ¼ teaspoon black pepper
- 1 teaspoon balsamic vinegar
Topping and Finishing
- ½ cup grated Gruyère cheese (or Swiss cheese)
- 1 egg, beaten with 1 tablespoon water (for egg wash)
Instructions
- Preheat Oven: Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper to prevent sticking.
- Caramelize Onions: In a large skillet, heat the butter and olive oil over medium heat. Add the sliced onions along with salt, black pepper, and thyme. Cook slowly, stirring occasionally, until the onions become deeply golden and caramelized, about 25 to 30 minutes.
- Add Balsamic Vinegar: Stir in the balsamic vinegar and cook for an additional 1 minute to enhance the flavor. Then remove the skillet from heat and allow the onions to cool slightly.
- Prepare Puff Pastry: On a lightly floured surface, roll out the thawed puff pastry and cut it into 4 to 6 equal rectangles or circles, depending on your preference.
- Assemble Tarts: Place the pastry pieces on the prepared baking sheet. Carefully score a small border about ½ inch from the edges on each tart, then prick the center with a fork to prevent excessive puffing in the middle.
- Add Fillings: Spoon the caramelized onions evenly into the center sections of each tart and sprinkle the grated Gruyère cheese on top of the onions.
- Apply Egg Wash: Brush the scored edges of the puff pastry with the beaten egg wash to give the crust a beautiful golden color during baking.
- Bake: Bake in the preheated oven for 18 to 22 minutes, or until the pastry is puffed and golden brown.
- Serve: Remove from oven and serve warm or at room temperature. These tarts are perfect as an appetizer, lunch, or a light dinner alongside a fresh salad.
Notes
- You can prepare the caramelized onions up to 3 days in advance and store them refrigerated for convenience.
- For a richer and more complex flavor profile, try substituting Gruyère cheese with goat cheese or blue cheese.
- These tarts work wonderfully as appetizers or can be paired with a simple green salad for a casual lunch or dinner.
