Preheat oven to 375°F (190°C) and grease a pie dish.
In a skillet cook ground beef and diced onion until browned.
Drain excess grease and stir in pizza sauce, garlic powder, Italian seasoning, salt, and black pepper.
Spread the beef mixture evenly in the prepared pie dish.
Sprinkle shredded mozzarella cheese over the beef layer.
In a bowl whisk biscuit mix, milk, and eggs until smooth.
Pour the batter evenly over the filling.
Bake for 25–30 minutes until the top becomes golden and set.
Let the pie cool slightly before slicing and serving.
