Bring a large pot of salted water to a boil. Add the rotini pasta and cook according to package instructions until al dente. Drain and rinse under cold water.

In a mixing bowl, combine mayonnaise, sour cream, and Italian dressing. Whisk until smooth.

Fold the cooled pasta into the dressing, adding grated Parmesan cheese. Ensure the pasta is well-coat.

Fold in cucumbers, cherry tomatoes, red onion, black olives, red bell pepper, and parsley.

Season with salt and pepper to taste. Adjust flavors as needed.

Cover and refrigerate for at least 1 hour to meld flavors.

Gently stir before serving. Serve chilled.