Cook the pasta: Bring a large pot of water to a boil. Add the rotini pasta and cook according to package instructions until al dente. Drain and rinse under cold water to stop the cooking process and cool the pasta.
Combine ingredients: In a large bowl, mix the cooked and cooled pasta with the diced chicken, halved cherry tomatoes, diced cucumber, diced red bell pepper, finely chopped red onion, cooked bacon (if using), and shredded cheddar cheese.
Prepare dressing: In a separate small bowl, combine mayonnaise, Dijon mustard, apple cider vinegar, and salt and pepper to taste. Whisk until smooth and creamy.
Mix salad: Pour the dressing evenly over the pasta salad ingredients and gently mix until all ingredients are well coated with the dressing.
Taste and adjust: Taste the salad and adjust seasoning with additional salt and pepper if desired.
Chill: Cover the salad with plastic wrap or a lid and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve: Before serving, give the salad a good stir, garnish with freshly chopped parsley, and serve chilled.
Notes
Serve in a large bowl or individual portions, garnished with extra cherry tomatoes or a squeeze of lemon for freshness.