Cook the potatoes and Jerusalem artichokes in boiling water for about 20 minutes. Peel, wash and cut carrots into small pieces. Peel onion and garlic and chop finely. Drain potatoes and Jerusalem artichoke, quench and peel. Press through a potato ricer. Knead in 100 g flour and egg yolks, season to taste with salt and nutmeg.
Form rolls (approx. 2 cm Ø) from the mixture on a floured work surface and cut into rolls of approx. 5 cm length. Beat the egg with 2 tablespoons of water in a plate. Put 6 tablespoons of flour and breadcrumbs on each plate. Turn the rolls first in flour, then in egg and finally in breadcrumbs. Heat frying oil in a pot. Fry the croquettes in it in portions until golden brown. Remove and keep warm. Heat the oil in a pan. Fry the minced meat in it while turning. Season with salt, pepper and marjoram. Add carrots, onion and garlic and fry briefly. Add tomatoes and tomato paste, bring to the boil and simmer for about 3 minutes.
Heat the oil in a pan. Fry the minced meat in it while turning. Season with salt, pepper and marjoram. Add carrots, onion and garlic and fry briefly. Add tomatoes and tomato paste, bring to the boil and simmer for about 3 minutes. Season to taste with salt and pepper. Arrange bolognese sauce and croquettes on plates. Garnish with marjoram