Ingredients
Scale
- 1 sheet puff pastry, thawed
- 2 tablespoons olive oil
- 4 large onions, thinly sliced
- 3 tablespoons balsamic vinegar
- 1 teaspoon sugar
- 1 teaspoon fresh thyme leaves
- Salt and pepper to taste
- 1 cup grated Gruyère cheese (or substitute with cheddar for a sharper flavor)
- 1 egg, beaten (optional, for brushing pastry edges)
Instructions
- Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
- Heat olive oil in a large skillet over medium heat. Add the sliced onions and cook, stirring occasionally, until they become soft and golden brown, about 20-25 minutes.
- Add the balsamic vinegar, sugar, thyme, salt, and pepper to the onions. Stir well and cook for another 5 minutes until the onions are deeply caramelized and fragrant. Remove from heat and let cool slightly.
- Roll out the puff pastry on a floured surface to smooth any creases and transfer it to the prepared baking sheet.
- Spread the caramelized onions evenly over the pastry, leaving a 1-inch border around the edges.
- Sprinkle the grated Gruyère cheese over the onions.
- Fold the edges of the pastry over the filling, creating a rustic border. Brush the edges with the beaten egg, if using, for a golden finish.
- Bake in the preheated oven for 20-25 minutes, or until the pastry is golden brown and the cheese is bubbling.
- Allow the tart to cool slightly before slicing and serving. Enjoy!
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Main Dish
- Method: Cooking
- Cuisine: International
Keywords: Caramelized Onion Tart, recipe, cooking, food