Begin by bringing a large pot of salted water to a rolling boil over high heat. Add rotini pasta and cook for about 8 minutes, or until al dente. Once done, drain the pasta in a colander and rinse it under cold water to stop the cooking process.

In a mixing bowl, combine mayonnaise, sour cream, dry ranch dressing mix, garlic powder, and milk. Whisk for about 2 minutes until smooth and creamy.

In a large mixing bowl, add the cooled pasta and pour the dressing over it. Toss gently to coat the pasta evenly. Fold in cooked bacon, diced tomato, sliced black olives, and shredded cheddar cheese. Ensure all the ingredients are well combined.

Cover the bowl with plastic wrap or transfer the salad to an airtight container. Refrigerate for at least 2 hours to allow the flavors to meld beautifully. If possible, let it chill overnight.