Bring a large pot of salted water to a boil. Add the pasta and cook according to the package instructions until it's al dente. Drain the pasta and rinse it under cold water to stop the cooking process. Drain well and cool completely.

In a medium bowl, whisk together the mayonnaise, sour cream, buttermilk, and ranch seasoning mix. Taste and add salt and pepper as desired. If you like a thinner dressing, you can add a little more buttermilk.

In a large mixing bowl, combine the cooked and cooled pasta with the cherry tomatoes, cucumber, red bell pepper, red onion, black olives (if using), and shredded cheddar cheese.

Pour the ranch dressing over the pasta and veggies. Gently toss until the salad is well coated with the dressing.

Cover the bowl with plastic wrap or a lid and refrigerate the pasta salad for at least 1 hour before serving. This allows the flavors to blend.

Just before serving, taste the salad and add more salt and pepper, if needed. Garnish the salad with fresh parsley for a pop of color and freshness. Serve ranch pasta salad as a side dish for picnics, barbecues, or alongside your favorite grilled meats.