Steps
1. Preheat oven to 200°C (400°F).
2. Heat olive oil and butter in a pan over medium heat.
3. Add sliced onions, a pinch of salt, and cook slowly, stirring occasionally, until deeply golden and caramelized (about 20 minutes).
4. Roll out the puff pastry on a baking sheet lined with parchment paper.
5. Spread caramelized onions evenly over the puff pastry, leaving a small border around edges.
6. Crumble goat cheese over the onions.
7. Sprinkle fresh thyme leaves, salt, and pepper.
8. Fold the edges slightly to create a border.
9. Bake in the preheated oven for 15-20 minutes or until pastry is golden and crisp.
10. Let cool slightly before serving.