Put the eggs in boiling water and boil them hard for about 10 minutes. Wash and peel the potatoes and cook them together with the caraway seeds in little boiling salted water for about 20 minutes. Rinse eggs under cold water and keep 4 eggs warm.
Peel the remaining eggs, halve them and let them cool down. Wash herbs, dab dry and chop except for something to garnish. Put some chives aside. Peel the garlic and press it through a garlic press.
Pass the egg yolk from the cooled egg halves through a sieve. Finely chop the egg white. Mix sour cream, yoghurt, egg yolk, mustard, garlic, oil and lemon juice. Stir in the egg whites and herbs, except for a tablespoon, and season to taste with salt and pepper.
If desired, stir the sauce with a few tablespoons of milk or cream to make it thinner. Drain the potatoes. Heat the fat in a saucepan, add the potatoes and the remaining chives. Peel and halve warm eggs and arrange on plates with the sauce and potatoes.
Serve sprinkled with remaining herbs and garnished.