Cook the rotini pasta following the instructions on the package until it reaches an al dente texture. Drain thoroughly and rinse under cold water to halt the cooking process and chill the pasta.
In a mixing bowl, blend the mayonnaise, sour cream, pickle juice, onion powder, and black pepper. Whisk until the dressing becomes velvety and uniform.
In a large serving bowl, combine the cooled pasta, diced cheddar cheese, sliced pickles, and fresh dill.
Drizzle the creamy dressing over the salad components. Gently fold the ingredients together until everything is well-coated and evenly mixed.
Cover the bowl and refrigerate until ready to serve. This salad is best enjoyed chilled.