1. cut the stem below the cabbage head into small pieces and remove all outer leaves.
2. with a small sharp kitchen knife cut a cone 2 cm deep from the stem, so the cabbage cooks more evenly.
3. put the eggs in boiling water and boil for 10 minutes until hard, then rinse and peel. Chop the egg whites, spread the egg yolks through a sieve, set both aside separately. Rinse and chop the parsley. Spread the breadcrumbs through a sieve.
In a large enough saucepan, bring enough salted water to a boil. Add 3 tbsp juice of one lemon and pour in the cabbage. With the lid half-open, cook over medium heat for 17-20 min until lightly simmering.
5. 5 minutes before the end of the cooking time, foam the butter in a frying pan and sweat the breadcrumbs in it over medium heat for 4 minutes while stirring. Add the egg whites, parsley and the remaining juice of one lemon, season with salt and pepper.
Remove the cabbage from the water, drain well and arrange on a platter. Pour the hot butter sauce over it and sprinkle with the egg yolk.
Serve with boiled potatoes.