First the basics. The best and easiest way to hardboil eggs!

Prick a hole in the wide end of the eggs and place in a pan. Add enough water to go one inch over the eggs. Bring to a rolling boil. Turn OFF the heat, cover, and set your timer for 12 minutes. After the 12 minutes, drain the hot water and immediately add cold water. Add a handful of ice cubes to help cool the eggs so they stop cooking.

Shell the eggs, then cut the eggs in half lengthwise. Put the whites on a pretty plate. Mash the yolks in a bowl with the mayonnaise, mustard, salt and pepper. If you have a cookie press, fit it with a tip that you can squeeze the yolk mixture out of and use that to fill the eggs. If not, you can put the yolk mixture in a plastic sandwich bag and cut the tip off one corner and squeeze it through that. If all else fails, use a spoon and a knife to scrape the yolk into the egg whites!