Pound beef slices well and sprinkle salt on both sides. Pound the bacon slices well to flatten as much as possible. On top of each beef slice, place 1 bacon segment.
Wash sauerkraut, then squeeze it. Divide the sauerkraut into 6portions and place one on top of each bacon-beef slice. Top sauerkraut with sausage slices. Spoon 1cup of the sour cream evenly on top of the sausage layer.
Carefully roll up each beef slice with its topping; make sure none of the filling falls out. Tie each roll with string.
Use a large frying pan. Heat half of the lard and fast-fry the meat roulades on all sides.
Brown chopped onion in remaining lard in a heavy stewing pot; sprinkle paprika in, stir, and immediately add chopped tomato and 1cup water. Place the browned roulades next to each other in the tomato mixture. Sprinkle with salt. Add marjoram and garlic, and cover the pot with a heavy lid.
Cook this dish over very low heat. Make sure you do not stir it, but grab both sides of the pot by the handles and make fast quarter turns if necessary to keep meat from sticking or burning.
When meat is done, remove from the pot and let stand for 5 minutes, then cut strings.
Cook the liquid in the pot until it becomes as thick as a sauce. Mix remaining sour cream, the light cream and flour, and stir into the gravy; bring to a boil and simmer for 5 minutes. Remove garlic. Force the sauce through a sieve or purée in a blender.
Pour sauce back into the pot, add white wine, and bring again to a boil. Simmer for a couple of minutes.
Place the rolled rostélyos on a serving platter and pour the sauce on top.