Boil the eggs hard for about 10 minutes. Peel and finely dice the onion
Heat the fat in a pot. Brown the diced ham in it. Add onion and fry until transparent. Sprinkle with flour and sauté briefly. Stir in milk, 1/4 l water and stock. Bring to the boil and simmer for about 5 minutes. Stir in mustard
Bring 3/4 l water to the boil and pour into a bowl. Stir in the purée. Stir vigorously again after 1 minute
Quench 4 eggs, peel and possibly halve them. Season the sauce with salt and pepper. Heat the eggs in the sauce. Wash the chives, cut them into small rolls and sprinkle over them. Serve everything. Gherkins taste good with it