Amanda's Stuffed Peppers

Preheat the oven to 350 degrees F (175 degrees C). Line a 9x13-inch baking dish with aluminum foil.

Mix together ground beef, bread crumbs, Italian seasoning, garlic, 1/2 cup mozzarella cheese, 1/2 cup Parmesan cheese, egg, onion, and mushrooms in a large bowl. Spoon mixture evenly into the seeded bell peppers. Replace the tops. Place stuffed peppers in the prepared dish.

Bake in the preheated oven until meat stuffing is cooked through, about 1 hour. Remove from the oven and discard the pepper tops.