Bosnian Börek with Spinach and Feta

Method

1. Preheat oven to 375°F (190°C).
2. In a pan, sauté onion until translucent.
3. Add spinach and cook until wilted.
4. Mix in feta cheese, salt, and pepper.
5. Roll out the puff pastry and cut into a large rectangle.
6. Spread the spinach and feta mixture over the pastry.
7. Roll the pastry tightly, then cut into individual pieces.
8. Brush with beaten egg and bake for 25-30 minutes until golden brown.