Preheat the oven to 350 degrees F.
Roll out the dough to 1/4 inch thick and cut into 3-inch squares. Place a heaping tablespoon of the meat filling in the center of each one and place a bit of the mozzarella on top. Brush the edges with the egg wash and fold over, forming a triangle. Press down on the edges with a fork and place on a baking sheet lined with parchment paper. Brush the tops with the egg wash and poke a little hole in the top of each one to let the steam escape.
Bake until golden brown, about 20 minutes. Cool slightly before serving.