Add water, salted water, and boil the rotini until it is al dente. Add water and drain, rinse under cold water to end the cooking. This makes the salad light and fresh.
Whisk mayonnaise, sour cream, vinegar, sugar, mustard, garlic powder, salt, and pepper in a small bowl. Taste it. Adjust. This dressing must be creamy, tangy, and slightly sweet.
Cut the bell pepper, cucumber, and onion into small and equal sizes. The smaller your cut, the more it is mixed in the salad.
Add the cooled pasta and veggies to your big mixing bowl. Add the dressing, then mix until all pasta spirals are covered.
Relax and refrigerate for at least one hour (two is better). The tastes require time to mix.
serve with parsley, perhaps with a sprinkle of that cheese, and eat cold.