Shred cabbage, carrot, and onion.
Beat eggs with salt and pepper, then add the shredded vegetables and mix well.
Spread butter on a pan and toast both sides of the bread until crispy.
Add oil to the pan, spread the egg and vegetable mixture thinly, and cook until done.
Place the cooked egg and vegetables on top of a slice of bread.
Add sugar, ketchup, and mayonnaise to taste.
Cover with another slice of bread to finish.