Bring about 1 ½ liter of salted water to the boil with the caraway seeds. When it boils (important!) Stir in the sour milk and add the egg slices. Bring to the boil and season with salt (be careful, not too much, you can always add salt at the table!).
Roast the jacket potatoes well in lard or oil, cut a little with a fork, season with salt and sprinkle with the parsley.
Serve the soup hot, serve with the roasted potatoes and enjoy.