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, basil, and red onion.
In a separate small bowl, whisk together the balsamic vinegar, olive oil, garlic powder, salt, and pepper.
Pour the dressing over the pasta salad and toss gently to combine.
Chill the salad in the refrigerator for at least 30 minutes before serving to allow the flavors to meld.
Serve chilled or at room temperature, garnished with additional basil if desired.
