Preheat oven to 350°F. Grease a 9x13-inch baking pan and set aside.
Cook pasta according to package directions; drain and set aside.
In a skillet, brown the ground beef over medium heat. Add onion, green pepper, and mushrooms, cooking 5-10 minutes until vegetables are softened.
Stir in tomato sauce, olives, sugar, salt, pepper, Italian seasoning, and pepperoni. Simmer for 5 minutes. Taste and adjust seasoning with salt and pepper as needed.
Combine the sauce mixture, 1/2 cup of each cheese with pasta, then spread into the prepared pan. Top with the remaining two cheeses.
Bake for 25 minutes, until bubbly and cheese is melted. Enjoy!