Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.
In a large mixing bowl, combine the cooled pasta, cherry tomatoes, mozzarella balls, and chopped basil.
In a separate bowl, whisk together the mayonnaise, sour cream, balsamic vinegar, garlic powder, salt, and pepper until smooth.
Pour the dressing over the pasta mixture and toss gently to combine, ensuring everything is evenly coated.
Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld.
Before serving, give the salad a gentle toss and adjust seasoning if necessary.
