Slice sausage. Cook until well browned. Reserve one egg yolk. Combine rest of eggs with sausage, spinach, mozzarella, ricotta, salt, pepper and garlic powder. Make pastry and divide, making on piece slightly larger. Shape into balls. On floured surface, roll out larger ball. Place in deep pie pan. Add filling. Roll smaller dough ball and place on top. Trim edges and fold under. Slit top. Combine yolk with water. Brush top of pie. Bake in preheated 375 degree oven 1-1/4 hours. Let stand 10 minutes. Serve hot or cold.