In a bowl, whisk together eggs, mayonnaise, sugar, and milk until smooth.

Add diced hanpen to the egg mixture and gently mix to combine.

Heat a non-stick frying pan over medium heat and lightly coat with salad oil.

Pour half of the egg mixture into the pan and cook until the surface is slightly set.

Roll the cooked egg to one side of the pan, then pour the remaining mixture and cook until set.

Roll the entire egg mixture into a log shape and cook until golden brown on all sides.