Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.
In a large bowl, combine the cooled pasta, cherry tomatoes, mozzarella balls, and chopped basil.
In a small bowl, whisk together the pesto sauce, olive oil, salt, and black pepper.
Pour the pesto mixture over the pasta salad and toss gently to combine.
Sprinkle the grated Parmesan cheese on top and toss again.
Chill the salad in the refrigerator for at least 30 minutes before serving to allow the flavors to meld.