Steps
1. Preheat the oven to 200°C (390°F).
2. Heat olive oil in a pan over medium heat. Add sliced onions and cook slowly until soft and golden, about 15 minutes.
3. Sprinkle brown sugar over the onions and continue cooking for another 5 minutes until caramelized. Season with salt, pepper, and thyme.
4. Roll out the puff pastry on a baking sheet lined with parchment paper.
5. Spread the caramelized onions evenly over the pastry, leaving a small border around the edges.
6. Crumble goat cheese over the onions.
7. Fold the edges of the pastry slightly over the filling to create a border.
8. Bake in the preheated oven for 20-25 minutes, until the pastry is golden and crisp.
9. Let cool slightly before serving.