Carefully remove the yolks into a small mixing bowl. Using a fork, mash the yolks and mix it with mayonnaise, sour cream, and mustard. Season it with salt and pepper.
Spoon the yolk mixture and put it in a cake icing bag. Pipe out the mixture into the egg white cups. Garnish it with a dash of paprika, and chopped parsley if desired.
Notes
Per 1 serving: 74 calories, 7g fat, 3g protein, 1g total carbs