Cook pasta in boiling salted water until al dente, about 7 to 9 minutes. Drain, rinse under cold water, and shake dry.

In a small bowl, whisk olive oil, red wine vinegar, oregano, garlic powder, salt, and pepper until the salt dissolves.

In a large bowl, combine pasta, pepperoni, tomatoes, mozzarella, bell pepper, olives, and red onion. Pour about three-quarters of the dressing over the top and toss gently.

Add Parmesan and the remaining dressing if needed, toss once more, and serve right away or let sit 10 minutes. Top with fresh basil if you like.