Description
These Caramelized Onion Tarts feature sweet, golden onions slow-cooked to perfection and baked atop flaky puff pastry with Gruyère cheese, making a deliciously elegant appetizer perfect for any occasion.
Ingredients
Scale
For the Caramelized Onions
- 2 tablespoons olive oil
- 2 large yellow onions, thinly sliced
- 1 tablespoon butter
- 1 teaspoon sugar
- ½ teaspoon salt
- ¼ teaspoon black pepper
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme)
For the Tarts
- 1 sheet puff pastry, thawed
- ½ cup grated Gruyère cheese
- 1 egg, beaten (for egg wash)
- Optional: balsamic glaze and fresh thyme for garnish
Instructions
- Prepare the Oven: Preheat your oven to 400°F (200°C) to ensure it reaches the perfect temperature for baking the tarts evenly and getting that golden puff pastry crust.
- Caramelize the Onions: In a large skillet over medium heat, warm the olive oil and butter until melted. Add the thinly sliced onions and stir to coat them in the oil and butter. Cook the onions slowly for 25–30 minutes, stirring occasionally until they become soft, golden, and deeply caramelized. About halfway through cooking, sprinkle in the sugar, salt, black pepper, and thyme to enhance the caramelization and flavor development.
- Prepare the Puff Pastry: While the onions cook, lightly flour a surface and roll out the thawed puff pastry sheet. Cut the pastry into 4 to 6 equal squares or circles based on your preferred tart size. Transfer the cut pieces onto a parchment-lined baking sheet and prick the center of each piece lightly with a fork, making sure to leave a ½-inch border untouched around the edges to allow them to puff properly.
- Assemble the Tarts: Sprinkle a small amount of grated Gruyère cheese in the center of each pastry piece. Spoon the caramelized onions over the cheese, distributing them evenly without covering the edges.
- Apply Egg Wash: Using a brush, carefully apply the beaten egg around the edges of each tart. This will give the crust a beautiful, golden shine when baked.
- Bake: Place the baking sheet in the preheated oven and bake the tarts for 18–22 minutes, or until the puff pastry is golden brown and puffed up perfectly.
- Finish and Serve: Remove the tarts from the oven and let them cool slightly. Optionally, drizzle with balsamic glaze and garnish with fresh thyme before serving for an added touch of flavor and presentation. Serve warm or at room temperature.
Notes
- You can prepare the caramelized onions in advance and refrigerate them until ready to assemble and bake the tarts.
- For a different flavor profile, substitute Gruyère with Brie or goat cheese.
- Serve these tarts as an elegant appetizer or starter, perfect for parties and gatherings.
