Boil the eggs on low heat for about 20 minutes while rolling them gently with chopsticks to center the yolks.

Cool the boiled eggs in cold water and peel off the shells.

Cut off the bottom ends of the egg whites slightly to make them stand upright, then cut the eggs in half and remove the yolks.

Dice the slice of ham and finely chop the cucumber after peeling it.

Mix the egg yolks with diced ham, cucumber, mayonnaise, mustard, salt, and pepper.