Preheat Oven:
Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Prepare the Filling:
In a large skillet, heat the olive oil over medium heat.
Add the chopped spinach and cook until wilted, about 2-3 minutes.
Remove from heat and allow to cool slightly.
In a medium bowl, combine the cooked spinach with ricotta cheese, Parmesan cheese, garlic powder, salt, and pepper. Mix thoroughly.
Assemble the Pastries:
Roll out the puff pastry sheets on a lightly floured surface.
Cut each sheet into 4 squares (total of 8 squares).
Place a spoonful of the spinach and cheese mixture in the center of each square.
Fold the pastry over to form a rectangle or triangle, and press the edges with a fork to seal.
Transfer the pastries to the prepared baking sheet.
Apply Egg Wash:
Brush the tops of the pastries with the beaten egg for a golden finish.

Bake:
Bake in the preheated oven for 15-20 minutes, or until the pastries are puffed and golden brown.

Enjoy your homemade spinach-stuffed pastries!