Clean the mushrooms and cut them into thin slices. Saute them in the butter with the finely chopped parsley. Sprinkle them with salt and black pepper to taste.
Separately, prepare a thick mixture of the egg yolks, flour and carbonated water. Add the mushrooms and beaten to snow egg whites.
Put the mixture into a pan with heated oil. Once the omelette is ready, arrange thin strips of ham on top of it. Sprinkle it with finely chopped parsley.