In a bowl mix the mayonnaise with the condensed milk. Set this aside for now.
Melt butter in a pan over low heat.
Pour the beaten eggs and let it set without moving it. Add the bread slices and let it soak up the egg a bit. When the egg has finally set, flip it with the breads using a large spatula.
Pile the following ingredients on one side: cheese, ham, cabbage then spread the sweetened mayonnaise on the other bread.
Fold the sides of the egg before finally folding the sandwich. Slice into a triangle and serve.