Cook macaroni noodles according to package directions. Drain and rinse noodles in cold water. Set aside.
In a large bowl, mix together mayonnaise, sour cream, fresh dill, Dijon mustard, and minced garlic. Add macaroni, radishes, and green pepper. Stir to combine.
Add cayenne, salt, and pepper. Stir well to combine.
Cover the salad and chill in the fridge for at least two hours before serving.
Notes
This creamy pasta salad is perfect for summer gatherings and can be made a day ahead. Feel free to add cucumbers or cheese for extra flavor and texture.