Peel and wash the carrots. Peel 2 onions. Cut carrots and onions into pieces. Wash the meat and dab dry. Season with salt and pepper. Heat the lard in a roaster. Brown the meat thoroughly all around.
Fry the carrots, onion pieces and bay leaf briefly. Brown the tomato puree. Deglaze with beer, cover and braise in the preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: level 2) for about 3 1/2 hours.
After about 1 hour, gradually add 1/2-3/4 litres of water. In the meantime clean and wash the Brussels sprouts. Cook in boiling salted water for 15-20 minutes, drain. Peel 2 onions and dice them finely. Cut bacon into fine strips.
Wash and chop the thyme. Melt 1 tablespoon of butter and sauté onions. Take out half of the onions. Add bacon to the onions in the pan and fry. Add Brussels sprouts and toss in.
Knead the remaining bacon and onion cubes, thyme and dumpling dough. Season with salt and pepper. Form into a roll and cut into approx. 1 cm thick slices. Heat 1 tablespoon butter. Fry the slices on each side until golden brown.
Remove the roast and let it rest for a short time. Let the stock boil down over high heat for about 5 minutes, thicken slightly if necessary, season to taste. Serve everything.