Creating Feta Cheese Foldovers is straightforward if you follow these steps:

1. Preheat Oven: Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
2. Prepare Filling: In a mixing bowl, combine the crumbled feta, chopped spinach, sun-dried tomatoes, parsley, black pepper, and salt. Mix well until all ingredients are evenly distributed.
3. Roll Out Pastry: On a lightly floured surface, roll out each sheet of puff pastry to smooth out any creases.
4. Cut Pastry: Cut each sheet into squares, approximately 4×4 inches in size.
5. Add Filling: Place a generous tablespoon of the feta mixture in the center of each pastry square.
6. Fold Over: Fold the pastry over to create a triangle shape, sealing the edges by pressing down with a fork.
7. Prepare Egg Wash: In a small bowl, beat the egg and brush it over the top of each foldover for a golden finish.
8. Drizzle Olive Oil: Lightly drizzle olive oil over the foldovers for added flavor and richness.
9. Sprinkle Sesame Seeds: If desired, sprinkle sesame seeds on top for an added crunch.
10. Bake: Place the foldovers on the prepared baking sheet and bake for 25 minutes, or until golden brown and puffed.
11. Cool: Remove from the oven and allow to cool slightly before serving.

Following these steps will lead you to an incredible batch of Feta Cheese Foldovers that will leave everyone asking for more.