Begin by bringing a large pot of salted water to a rolling boil. Add medium shell pasta and cook according to package directions until al dente, about 8-10 minutes. Once cooked, drain the pasta and run it under cold water.

In a large mixing bowl, combine the cooled pasta with 1/2 cup of dill pickle juice, tossing to ensure it is coated evenly. Allow the pasta to marinate for 5 minutes.

In a medium bowl, whisk together mayonnaise, sour cream, 4 tablespoons of dill pickle juice, and cayenne pepper until smooth. Adjust seasoning if necessary.

In your large bowl, combine the marinated pasta, diced cheddar cheese, sliced dill pickles, minced white onion, and chopped fresh dill. Drizzle the prepared dressing over the mixture and toss gently to coat.

Cover the bowl with plastic wrap or transfer to an airtight container. Refrigerate for at least 1 hour before serving to allow flavors to meld.