Cook the eggs in boiling water for about 8 minutes. Heat 2 tablespoons of fat in a pot, sauté flour in it, deglaze with broth and cream and bring to the boil. Stir in mustard, season with salt and pepper. Bring 3/8 litres of water and 1/2 teaspoon salt to the boil. Remove the pot from the heat, add milk and 1 tablespoon of fat. Stir in puree flakes and let it swell for about 1 minute.
Quench eggs cold, peel and halve them. Add eggs to the sauce. Roast mustard seeds in a pan without fat. Arrange egg ragout and mashed potatoes on plates. Sprinkle with the mustard seeds