Cook ground turkey or beef in a skillet over medium heat until browned. Drain excess fat if needed.
Stir in marinara sauce, garlic powder, Italian seasoning, salt, and pepper. Simmer for 2–3 minutes.
Preheat oven to 180°C / 350°F. Lightly spray a baking dish.
Spread the meat mixture evenly, then layer mushrooms, peppers, and olives.
Sprinkle mozzarella and Parmesan evenly over the top.
Bake for 20–25 minutes until hot and bubbly and cheese is melted.
Let cool for a few minutes before serving.
