The trick with the filling is to ensure that the combination is thick enough to hold its shape, moist enough not to taste chalky, and smooth enough not to resemble egg salad.
Tradition calls for a blend of mayonnaise and a bit of heat. The key, according to Cook's Illustrated magazine, is to find a balance free of egg overtones. For the mayonnaise, go with the real thing. Salad-dressing spreads tend to be too sweet.
For the "deviling," a blend of cayenne pepper and Dijon mustard works best. A splash of lemon juice heightens everything.
Some people swear by mashing the cooked yolks with a fork, but this can be tedious and leave egg-saladlike lumps. It's better to push the yolks through a wire mesh strainer, then mix them with the other filling ingredients. Letting the yolk mixture chill for a bit before filling the egg whites also gives it better body.
A piping bag can be fitted with decorative tips that allow for precise and attractive filling. Aim for about 2 ounces of filling per egg half -- or enough to come about ½ inch above the white. This amount should easily hold a peaked shape without tipping.
-- The Associated Press