Caramelized Onion Tart

1.Preheat the oven to 400°F (200°C).

2.Peel and thinly slice the onions.

3.In a large skillet, heat the butter and olive oil over medium heat.

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

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

6.Season the onions with salt and pepper to taste and remove from heat.

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

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

9.Sprinkle the grated Gruyere cheese over the onions.

10.Top with fresh thyme leaves for added flavor.

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

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

13.Enjoy your delicious Caramelized Onion Tart!