Prepare the onions, the leek, the carrot, the pickles and the parsley and put all of it in separate little plates.
Open the roulades and one after the other prepare them. Beat the meat with a meat tenderizer, spread some mustard on the meat slice, put a slice of bacon, some onion slices, parsley. Now roll the roulade into a roll and fix the ends with some toothpicks. Spread some tapioca flour on the roulade. Proceed until you have 8 beef rolls.
In a big crock pot or stew pot put some olive oil, let it heat and stir-fry the roulades from all sides that they are golden. Take them out and place them on a dish, set aside. Now add the carrot, leek and the remaining of the onion into the crock pot and stir-fry. Add the tomato paste, stir-fry, add half of the wine and let it simmer until the wine is nearly all gone.
Now put back the roulades into the crock pot, add the rest of the wine and the water, season with salt and pepper. Cover the pot with its lit and let it cook/braise for an hour and a half. From time to time turn the roulades.
The beef rolls are ready when you touch them with a spoon and the meat feels soft. Now take the meat rolls out and place them again on a dish. With a hand blender blend the vegetables and the sauce into a thick gravy. There is now additional flour needed. Season again if necessary. Put back the rouladen and let cool out or serve with red cabbage and potatoes.
The German Beef Rolls are best the day after, similar to a stew. You can also freeze portions of them, they will be perfect in any minute.