Wash and chop the marjoram. Bring the milk to the boil, remove from the heat and stir in the purée flakes. Stir the diced ham and marjoram into the potato dough and work through well. Use two tablespoons to form dumplings from the mixture.
For the pan, clean and wash the leeks and cut them into rings. Wash the apple, cut in half and cut out the core. Cut the flesh into slices and sprinkle with lemon juice. Wash liver, dab dry and turn lightly in flour.
Heat 1 tablespoon of oil. Fry the liver in the hot oil for about 2 minutes on each side, season with salt and pepper, remove and keep warm. Sauté leek and apples in the frying oil. Deglaze with cider and cook for about 8 minutes while turning.
Heat the remaining oil. Fry the gnocchi over medium heat, turning several times for 8-10 minutes. Drain on kitchen paper. Season apple-porree-pan, add liver to the leek-pan.
Serve everything sprinkled with a dash of crème fraîche and fresh marjoram leaves.