Wash the potatoes and cook them covered in plenty of boiling water for about 20 minutes
Wash parsley, shake dry, pluck leaves from the stalks and chop. Cut the remaining onion into slices. Drain potatoes, quench, peel and press through a potato ricer. Add egg and starch to the potatoes and mix. Flavour with nutmeg and salt. Form 12-16 dumplings from the potato dough
Boil up plenty of salted water. Add the dumplings and let them simmer for 15-20 minutes at low heat until they rise to the surface
In the meantime peel the onions. Dice 1 onion. Cut the chorizo into slices. Heat the oil and fry the chorizo for about 4 minutes while turning. Remove the sausage and fry the diced onion in the sausage fat for about 3 minutes until transparent. Add the tomatoes and chop them coarsely with a spatula and let them simmer for about 10 minutes. Season to taste with salt, pepper and sherry
Remove the dumplings. Heat the fat in a pan. Fry the dumplings for about 6 minutes. After about 3 minutes add onion slices. Arrange dumplings, sauce and sausage. Sprinkle with parsley