Caramelized Onion Tart

1Preheat the oven to 400°F (200°C).

2In a large skillet, melt the butter (1 tablespoon) with olive oil (1 tablespoon) over medium heat.

3Add the thinly sliced onions (2 large) and cook, stirring occasionally, until they are soft and golden brown, about 20-25 minutes.

4Sprinkle sugar (1 teaspoon) over the onions (2 large) and continue cooking for another 5 minutes until the onions (2 large) are caramelized.

5Roll out the puff pastry on a baking sheet and prick the surface with a fork.

6Spread the caramelized onions (2 large) evenly over the puff pastry, leaving a border around the edges.

7Sprinkle the grated Gruyere cheese (½ cup) over the onions (2 large).

8Bake in the preheated oven for 20-25 minutes or until the pastry is golden brown and the cheese is melted and bubbly.

9Garnish with fresh thyme leaves before serving.