01 - Boil rotini or penne in generously salted water until al dente, following package directions. Drain in a colander, rinse under cold running water, and spread on a tray to cool completely.
02 - In a large mixing bowl, whisk together mayonnaise, sour cream, and ranch seasoning mix until smooth. Stir in 1 tablespoon of milk, adding a second tablespoon if a thinner consistency is preferred.
03 - Add the cooled pasta to the dressing and toss thoroughly until every piece is evenly coated.
04 - Gently fold in the halved cherry tomatoes, diced bell pepper, shredded cheddar, bacon bits, sliced green onions, and thawed peas, taking care not to crush the tomatoes.
05 - Mix until all components are evenly distributed. Taste and adjust seasoning with salt and pepper as needed.
06 - Cover and refrigerate for at least 30 minutes to allow the flavors to meld. Serve cold.