Ingredients
- 1 sheet puff pastry, thawed
- 2 tablespoons olive oil
- 3 large onions, thinly sliced
- 1 teaspoon sugar
- 1 teaspoon balsamic vinegar
- Salt and pepper to taste
- 1 cup grated Gruyere cheese
- 1 teaspoon fresh thyme leaves
- 1 egg, beaten for egg wash
Instructions
1. Prepare the Puff Pastry: Preheat your oven to 400°F (200°C). Roll out the thawed puff pastry into a rectangle on a lightly floured surface. Place the pastry on a baking sheet lined with parchment paper.
2. Sauté the Onions: In a large pan, heat the olive oil over medium heat. Add the sliced onions and cook, stirring occasionally, until they begin to soften. Sprinkle with sugar and balsamic vinegar, and continue cooking for about 15 minutes or until the onions are deeply caramelized. Season with salt and pepper to taste.
3. Assemble the Tart: Sprinkle half of the grated Gruyere cheese onto the puff pastry, leaving a small border around the edges. Spread the caramelized onions over the cheese thyme leaves and top with the remaining cheese. Fold over the edges of the pastry to create a border.
4. Bake the Tart: Brush the edges of the pastry with the beaten egg. Bake for 20-25 minutes or until the pastry is golden brown and the cheese is bubbly.
5. Garnish and Serve: Remove the tart from the oven and let it cool for a few minutes. Garnish with fresh thyme leaves. Cut into squares or slices and serve warm.
Tips
- For an extra-flaky crust, keep the puff pastry cold until you’re ready to use it.
- To avoid a soggy tart, make sure to caramelize the onions thoroughly to remove excess moisture.
- Experiment with different types of cheese, like blue cheese or aged cheddar, for a new flavor twist.
- Add a sprinkle of nuts like walnuts or pecans for a crunchy texture.
Nutrition Information
- Calories: 320
- Total Fat: 20g
- Saturated Fat: 7g
- Trans Fat: 0g
- Cholesterol: 35mg
- Sodium: 220mg
- Total Carbohydrates: 26g
- Dietary Fiber: 2g
- Sugars: 5g
- Protein: 9g