In a medium bowl, combine the cooked shrimp, lemon juice, olive oil, granulated garlic, and cumin. Toss well to ensure the shrimp are evenly coated. Allow them to marinate for about 10 minutes at room temperature.

Heat a skillet over medium heat and add the marinated shrimp. Sauté for about 5 minutes, stirring occasionally, until the shrimp turn pink and are cooked through. Transfer them to a plate to cool down.

In a separate large bowl, whisk together sour cream, mayonnaise, Worcestershire sauce, brown sugar, mustard powder, salt, and pepper until smooth and creamy.

In a large bowl, add the cooked macaroni, sautéed shrimp, chopped shallot, celery, and chopped parsley. Gently fold the ingredients together.

Pour the creamy dressing over the pasta mixture and toss gently until all the ingredients are well coated.

Cover the bowl with plastic wrap or a lid and refrigerate the salad for at least 30 minutes before serving.