01 - Preheat oven to 175°C. Lightly grease a 23x33 cm baking dish.
02 - Bring a large pot of salted water to a boil. Add macaroni and cook until just al dente. Drain and set aside.
03 - Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook, breaking it apart, until browned. Drain excess fat if needed.
04 - Add diced onion, bell pepper, garlic, and mushrooms (if using) to the skillet. Sauté for 5 minutes until the vegetables have softened.
05 - Stir in crushed tomatoes, tomato sauce, tomato paste, oregano, basil, salt, and pepper. Simmer for 10 minutes, stirring occasionally.
06 - Add the cooked pasta to the skillet and toss to evenly combine with the sauce.
07 - Spread half of the pasta mixture into the prepared baking dish. Sprinkle with half of the cheddar and mozzarella cheeses.
08 - Top with the remaining pasta mixture and finish with the remaining cheeses.
09 - Bake uncovered for 25 to 30 minutes, until the cheese is melted and bubbling.
10 - Let the casserole rest for 5 minutes before portioning and serving.