Cut the rolls into cubes of about 1 cm. Peel and finely dice the onions. Melt 2 tablespoons of fat, fry one onion in it. Add milk. Season with salt, pepper and thyme, pour over the rolls, mix and let it swell for 10 minutes.
Whisk eggs and flour. Stir into the rolls, season to taste again. Form the roll mixture on a damp tea towel as a roll (approx. 8 cm Ø). Wrap up and tie the ends of the cloth together.
Cook in a long pot in plenty of slightly boiling salted water for about 45 minutes. In the meantime dice bacon finely. Clean the mushrooms, halve the mushrooms. Leave out the bacon in a pan. Add 2 tablespoons of fat.
Fry the remaining onion cubes and mushrooms. Add the remaining mushrooms. Fry over medium heat for about 5 minutes. Season with salt and pepper. Deglaze with cream and stock, bring to the boil. Stir in sauce thickener, bring to the boil again and season to taste.
Dumplings unwrap, cut into slices. Serve with the ragout. Wash the parsley and, except for something to garnish, chop and sprinkle over the dumplings.