Peel and wash the potatoes, cover and cook in boiling salted water for about 20 minutes. Boil the eggs in boiling water for 6-8 minutes until they are waxy to hard.
In the meantime, melt butter in a pot for the mustard sauce. Dust with flour and sweat lightly while stirring. Gradually add 400 ml water and cream while stirring. Bring to the boil and simmer for about 5 minutes.
Stir in mustard and stock. Season sauce with salt, pepper and sugar. Keep warm.
Cut cress from the bed and stir into the sauce. Quench the eggs, peel them, cut them in half. Warm the eggs in the sauce. Drain the potatoes and arrange everything.