Caramelized Onion Tart

1Preheat the oven to 400°F (200°C).

2Peel and thinly slice the onions (2 large).

3In a large skillet, heat the butter (1 tablespoon) and olive oil (1 tablespoon) over medium heat.

4Add the sliced onions (2 large) to the skillet and cook, stirring occasionally, until they start to soften, about 5 minutes.

5Sprinkle sugar (1 teaspoon) over the onions (2 large) and continue to cook, stirring occasionally, until the onions (2 large) are caramelized and golden brown, about 20-25 minutes.

6Season the onions (2 large) with salt and pepper to taste and remove from heat.

7Roll out the puff pastry on a baking sheet lined with parchment paper.

8Spread the caramelized onions (2 large) evenly over the puff pastry, leaving a border around the edges.

9Sprinkle the grated Gruyere cheese (½ cup) over the onions (2 large).

10Top with fresh thyme leaves for added flavor.

11Bake in the preheated oven for 20-25 minutes or until the pastry is golden brown and crispy.

12Remove from the oven and let it cool slightly before slicing and serving.

13Enjoy your delicious Caramelized Onion Tart!