Cook pasta according to package directions for al dente pasta. Drain and rinse with cold water until pasta is room temperature. Place pasta in a large bowl.
Add cherry tomatoes, pepperoni, onion, bell pepper, mozzarella, parmesan, and olives to the bowl. Set aside.
In a separate bowl, add olive oil, vinegar, italian seasoning, garlic powder, salt, pepper, and red pepper flakes. Stir to combine.
Pour vinaigrette over pasta salad, then toss to coat. Refrigerate for 1 hour before serving. Pasta salad will keep for 3-4 days, refrigerated in a sealed container. Pasta WILL continue to soak up the dressing the longer it sits, so it may need a splash of olive oil and vinegar if it has been sitting for several hours.
I recommend serving your pasta salad within a few hours, because the pasta will continue to soak up the dressing as it sits.
If your pasta salad has been sitting for a while and beginning to dry out, add a splash of olive oil and vinegar to your pasta salad to add some moisture.
Vinaigrette can be substituted with your favorite Italian dressing if desired.