Shred cabbage and carrots finely.
Add salt and pepper to the eggs and beat them well.
Heat olive oil in a pan and stir-fry the vegetables.
Pour the egg mixture over the vegetables and cook in a round shape.
Spread mustard sauce on one side of the whole wheat bread and place the egg-vegetable patty on top.
Cover with another slice of bread and toast both sides in the pan until golden brown.