Preheat the oven to 375˚F. In a 10-inch skillet over medium heat, cook sausage and onion until browned, stirring frequently
Spoon off fat/grease from the sausage.
Add in the spinach and cook until wilted, about 1 to 2 minutes
In a large bowl, combine the sausage, spinach, mozzarella, ricotta, salt, pepper, and garlic powder. Set aside
On a lightly floured surface, fill each empanada with ½ cup of filling
Use a pastry crimper to crimp the outer edges
Bake for 15 minutes or until pies are golden brown