Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish.

Cook the pasta according to the package instructions until just al dente. Drain and set aside.

In a large skillet, heat a little olive oil over medium heat. Add the ground beef, Italian sausage, and diced onion. Cook until the meats are browned and the onion is soft. Drain any excess fat.

Stir in the garlic powder and Italian seasoning. Add the chopped pepperoni, diced ham, and cooked bacon. Cook for an additional 2-3 minutes. Remove from heat.

In a large bowl, mix the cooked pasta with the pizza sauce. Add the meat mixture and sliced mushrooms and black olives if using. Toss to combine everything well.

Spread half of the pasta and meat mixture into the prepared baking dish. Sprinkle with half of the mozzarella and cheddar cheese.

Add the remaining pasta and meat mixture, and top with the remaining mozzarella and cheddar cheese. Sprinkle with grated Parmesan cheese and arrange some pepperoni slices on top.

Cover with foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes or until the cheese is bubbly and slightly golden.

Let the casserole rest for a few minutes before serving. Garnish with fresh herbs like basil or parsley if desired.