Boil noodles according to package directions.

While noodles are cooking, heat olive oil in a large pan over medium heat.

Add minced garlic and chopped onion to the pan and sauté until softened and fragrant.

Add chopped bell pepper and continue to sauté until the vegetables are tender.

Add mushrooms, sliced olives, and Italian-style stewed tomatoes (with juice) to the pan. Cut up the tomatoes if they are in large pieces.

Pour in spaghetti sauce and add parmesan cheese. Stir everything together.

Quarter the pepperoni and stir it into the sauce.

Let the sauce simmer and bubble gently while the noodles finish cooking.

Drain the cooked noodles and return them to the pot.

Pour the sauce over the noodles.

Stir the noodles and sauce together to combine.

Cover the pasta with shredded cheese.

Cover the pot and let the cheese melt.

Serve immediately or stir the cheese into the pasta before serving.