Description
Deliciously rich and savory Caramelized Onion Tarts featuring flaky puff pastry topped with sweet, slow-cooked onions, fresh thyme, and melted Gruyère cheese. Perfect as an elegant appetizer or a light lunch, these French-inspired tarts combine deep caramelized flavors with a golden, buttery crust for an irresistible treat.
Ingredients
Scale
Pastry
- 1 sheet puff pastry (thawed)
Onion Filling
- 2 large yellow onions (thinly sliced)
- 2 tbsp unsalted butter
- 1 tbsp olive oil
- 1 tsp sugar
- 1/2 tsp salt
- 1/4 tsp black pepper
- 1 tsp fresh thyme leaves (or 1/4 tsp dried)
Topping
- 1/2 cup shredded Gruyère or Swiss cheese
- 1 egg (beaten, for egg wash)
Optional Garnish
- Fresh thyme or microgreens
Instructions
- Preheat Oven and Prepare Baking Sheet: Preheat the oven to 400°F and line a baking sheet with parchment paper to prevent sticking and ensure easy cleanup.
- Caramelize the Onions: In a large skillet, melt the butter with olive oil over medium heat. Add the thinly sliced onions, sugar, salt, and pepper. Cook, stirring occasionally, for 20–25 minutes until the onions turn a deep golden brown and are caramelized. Stir in the fresh thyme leaves and let the mixture cool slightly.
- Prepare the Puff Pastry Base: On a lightly floured surface, roll out the thawed puff pastry into a 10×12-inch rectangle. Cut the pastry into 6 equal rectangles and place them on the prepared baking sheet. Score a 1/2-inch border around each tart without cutting all the way through, then prick the centers with a fork to prevent excessive puffing.
- Add Egg Wash and Toppings: Brush the edges of each tart with the beaten egg to create a nice golden finish. Evenly distribute the caramelized onion mixture over the centers of each rectangle and sprinkle shredded Gruyère cheese on top.
- Bake the Tarts: Place the baking sheet in the preheated oven and bake for 15–18 minutes, or until the puff pastry is golden, puffed, and crisp. Remove from the oven and allow the tarts to cool slightly before serving.
- Garnish and Serve: Optional – garnish the tarts with fresh thyme or microgreens for an added touch of freshness and color. Serve warm as an elegant appetizer or light lunch.
Notes
- These tarts make a great appetizer or light lunch.
- You can prepare the caramelized onions ahead of time and store them in the fridge for up to 3 days.
- For extra richness, consider adding a dollop of crème fraîche or goat cheese on top before baking.
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Category: Appetizer
- Method: Baking
- Cuisine: French-Inspired
