Cut the potatoes into bite-sized pieces, then cook them until they are tender. Rinse them under cold water and rest.
Thinly slice the onion.
Heat the oil in a large pan and sauté the onion over low heat for 8 minutes.
Add the garlic, oregano, bay leaf and caraway seeds and fry for a minute.
Add the paprika, freshly ground pepper and the tomato purée, stir for about 10 seconds, then add the potatoes and sauerkraut, including its natural brine. Add some water, if needed.
Cook for about 10 minutes until you get a thick sauce around the potatoes.
Drain the lentils and add to the potatoes.
Warm through, then add the chopped parsley and a pinch of paprika and serve.