Peel the potatoes and cook in boiling salted water for about 25 minutes. In the meantime melt 30 g butter in a pot, stir in flour. Add stock and 250 ml milk while stirring, let simmer for about 5 minutes, stir occasionally.
Boil the eggs in boiling water for about 5 minutes in semi-liquid form or for about 8 minutes in waxy form. Quench eggs with cold water. Wash parsley and chop finely, except for a stalk. Add parsley to the sauce, except for 1 tablespoon, and season with salt and pepper.
Drain the potatoes, add 1/4 litre milk and 1 tablespoon butter and mash. Season to taste with salt, pepper and nutmeg. Sprinkle with the rest of the parsley. Peel and halve the eggs. Arrange eggs with sauce and potatoes and garnish with remaining parsley.