In a large skillet over medium heat, add the ground beef, Italian sausage, and chopped bacon. Cook for about 8-10 minutes, stirring occasionally, until the meats are browned and crispy. Drain any excess fat and set the meats aside.

In the same skillet, add diced onions and minced garlic. Sauté for 3-4 minutes until the onions become translucent and fragrant.

Mix in the canned diced tomatoes, tomato paste, Italian seasoning, salt, and pepper. Stir well and bring to a gentle simmer. Let cook for about 5-7 minutes.

Preheat your oven to 375°F (190°C). In a baking dish, layer half of the meat sauce, followed by half of the cheeses. Repeat with the remaining meat sauce and top with the rest of the cheeses.

Place the casserole in the oven and bake for 25-30 minutes until bubbly and golden brown.

Once baked, let the casserole rest for a few minutes. Garnish with parsley or basil and serve warm.