Cook the Shrimp: Bring a large pot of salted water to a boil. Add the shrimp and cook for 2–3 minutes until pink and opaque. Drain and cool under cold running water.

Cook the Pasta: In another pot, boil salted water and add macaroni. Cook until al dente (7–9 minutes), then drain and rinse under cold water.

Chop Vegetables: Wash and chop celery, red bell pepper, and green onions into small, uniform pieces.

Make Dressing: In a medium mixing bowl, whisk together mayonnaise, sour cream, Dijon mustard, lemon juice, dill, salt, and pepper until smooth.

Combine Ingredients: In a large bowl, combine cooled pasta, shrimp, and vegetables. Pour the dressing over and toss gently.

Chill Salad: Cover and refrigerate for at least 30 minutes to meld flavors.

Serve: Stir gently before serving, adjusting seasoning as needed.