These personal pita-pizzas cook up nice and crisp.
Preheat oven to 400 degree. Place pitas on a baking sheet. Dividing evenly, layer with mozzarella, onion, and tomato. Top each pita with 4 meatballs, pressing to push them in.
Bake until meatballs are cooked through, cheese is melted, and pitas are crisp, about 20 minutes. Serve immediately.