Preheat oven to 350°F. Spray a 9x13-inch baking pan with nonstick spray. Set aside.
Cook the pasta noodles for one less minute than the time listed on the package. Drain and set aside.
3 ½ cups rotini pasta
While the pasta cooks, brown the ground beef and sausage in a large frying pan. Cook until the meat is no longer pink, about 5-7 minutes.
½ pound ground beef, ½ pound Italian sausage
Stir in the salt, pepper, and garlic powder and cook for 1 minute. Transfer the meat to a bowl and set aside.
1 teaspoon garlic powder, ½ teaspoon salt, ½ teaspoon ground black pepper
Drain any excessive fat and save the drippings in the pan. In the same pan, sauté the onions, carrots, and green peppers until softened, about 5 minutes.
½ onion, ¼ cup shredded carrots, ½ cup chopped green bell pepper
Add the meat back to the pan, stir in the mushrooms (if using), and mix together.
4 ounces sliced mushrooms
Add the cooked pasta and pizza sauce and toss to combine. Pour the mixture into the prepared baking dish.
28 ounces pizza sauce
Flatten the mixture into an even layer, sprinkle with shredded cheese, and add the pepperoni slices.
1 cup shredded Colby jack cheese, ½ cup pepperoni slices
Bake for 20-25 minutes until bubbling and the cheese has melted.