Step 1: Bring a large pot of salted water to a rolling boil. Add 12 ounces of elbow macaroni (or small pasta shells) and cook according to the package directions until al dente. Immediately drain the pasta and rinse under cold running water to stop cooking and cool thoroughly. Spread on a baking sheet or transfer to a large bowl to drain.
Step 2: In a medium bowl, whisk together ½ cup of mayonnaise and ¼ cup of sour cream until smooth. Stir in ¼ cup of pickle juice, 1 teaspoon of garlic powder, and a pinch of salt and pepper to taste. Whisk vigorously until the dressing is creamy and pourable.
Step 3: In the bowl with your cooled pasta, pour the dressing over the top. Add 1½ cups of chopped dill pickles, ½ cup of shredded cheddar cheese, ¼ cup of diced red onion, and 2 tablespoons of fresh chopped dill (or 2 teaspoons dried). If desired, stir in ½ cup of chopped celery or a few tablespoons of sweet pickle relish for extra crunch. Toss gently but thoroughly to coat all ingredients evenly.
Step 4: Cover the bowl with plastic wrap or transfer the salad to an airtight container. Refrigerate for at least one hour—up to overnight—to allow the flavors to meld beautifully.
Step 5: Before serving, give the salad a final toss. Taste and adjust seasoning with additional salt, pepper, or another splash of pickle juice if you desire more tang. Garnish with extra dill sprigs or a sprinkle of cheddar, then serve chilled.