Bring a large pot of salted water to boil over high heat. Cook the pasta to al dente according to the package directions. Drain and set aside.

In a large skillet over medium-high heat, cook the ground beef until no longer pink, 7 to 8 minutes. Use a wooden spoon to break the beef up as it cooks. Transfer the beef to a plate and drain any excess fat from the skillet.

Add the olive oil to the skillet over medium-high heat. Add the garlic, onion, bell peppers, and mushrooms and cook until the vegetables are softened, 4 to 6 minutes.

Preheat the oven to 350° F. Spray a 13x9-inch baking dish or a 14-inch round baking dish with nonstick cooking spray.

Return the cooked ground beef back to the skillet and mix with the vegetables. Reduce the heat to low. Pour the pasta sauce into skillet. Add the Italian seasoning and mix well. Stir the cooked pasta into the skillet, making sure to evenly coat the pasta.

Transfer the mixture to the prepared baking dish. Top with the mozzarella and pepperoni. Bake uncovered until the cheese has melted, 20 to 25 minutes.