Bring a large pot of salted water to a boil. Once boiling, add cavatappi pasta and cook until al dente, about 7-9 minutes. Drain and rinse under cold water until cooled. Set aside.

In a large mixing bowl, whisk together the pesto sauce, mayonnaise, sour cream, chopped shallot, and lemon juice. Gradually add reserved pasta water until desired creaminess is reached. Season with salt and pepper.

In a serving bowl, combine cooled pasta with dressing. Gently fold in bacon, cherry tomatoes, arugula, Parmesan, and mozzarella. Toss until well coated.

Cover and refrigerate for at least 1 hour to allow flavors to meld. Toss gently before serving and garnish with additional Parmesan or herbs if desired.