Covered cranberries and sugar and simmer in a small saucepan for 3-4 minutes. Mix starch and 1 tablespoon of water and stir into the boiling cranberries. Simmer while stirring for about 1 minute.
(If the cranberries are too thick, stir in some water.) Season with salt and pepper. Wash, peel, halve or quarter the potatoes, then cook in salted water for about 20 minutes.
Cut bread into cubes and soak in milk for about 10 minutes. Peel and finely dice the onion. Knead minced meat, bread with the milk, egg and diced onion. Season with salt, pepper and paprika. Form 20 dumplings (each approx. 40 g) from the mixture.
Heat the oil in a pan. Fry the meatballs for at least 10 minutes over medium heat, turning them over. Drain the potatoes. Remove Köttbullar from the pan and arrange on plates with cranberries and potatoes.