Hard boil the eggs following the instructions above. Cool in cold water until you can handle the eggs if you’re going to peel immediately, or cool completely. You’ll have to change the water a time or two.
Slice the eggs in half lengthwise and remove the yolks. Place the whites on a plate and the yolks in a bowl.
Using a fork, mash the yolks until crumbly. Add the salt, mayonnaise and mustard, and mix well.