Slice the pork neck, but don`t cut it all the way through so that it stays in one piece. Season with salt, pepper and marjoram and rub thickly with mustard, especially between the slices. Put several slices of bacon and onion rings in each gap.
Soak wooden skewers in water and stick them through the meat from both narrow sides so that the slices do not pop open. Either wrap it tightly in aluminum foil and place it on a roasting bar or put it in a soaked Roman pot without foil, with the lid on Put in the oven at approx. 200 degrees for 1.5 hours. Then remove the foil or lid and cook for another 30 minutes. During this time, pour dark beer several times over.
White bread, garlic baguette or mashed potatoes go well with it.