Bring a large pot of salted water to a rolling boil over high heat. Add the multi-colored rotini pasta and cook for 6–8 minutes, or until al dente. Drain the pasta in a colander and rinse it gently under cold running water to cool it down completely.

In a large mixing bowl, combine the cooled pasta with half of the Italian dressing, kosher salt, and black pepper. Toss gently to coat the pasta evenly.

Carefully fold in the mozzarella cheese, cherry tomatoes, diced bell peppers, and sliced black olives into the pasta mixture, ensuring even distribution.

Transfer the pasta salad into large foil pans. Cover tightly with plastic wrap or aluminum foil and place in the refrigerator to chill for at least 4 hours, preferably overnight.