Cook macaroni noodles according to package directions. Drain. Rinse noodles in cold water. Set aside.

In a large bowl, combine mayonnaise, sour cream, chopped fresh dill, Dijon mustard, and minced garlic.

Add the cooked and drained macaroni, chopped radishes, and chopped green bell pepper to the bowl with the dressing.

Stir in the cayenne pepper, salt, and black pepper. Mix everything together until well combined.

Cover the bowl and refrigerate for at least two hours before serving to allow the flavors to meld.