Place eggs in a pot of cold, salted water. Bring the water to a boil and let eggs cook for about 10 to 15 minutes. Run eggs under cold water until they are completely cool. This ensures mess-free peeling. Always start peeling from the bottom of the egg, where the air bubble is usually located, and you will never have problems with sticky eggshells.
Cut eggs in half, lengthwise. Remove the egg yolks and mash them with fork in a small bowl. Mix in vinegar, shallots, mustard powder and mayo.
Spoon egg yolk mixture into small resealable plastic bag. Snip a small corner on the bottom of the bag. Dip egg whites and garnish of choice and then pipe egg yolk mixture into egg halves.
Refrigerate before serving.