Wash the leg slices, pat dry, cut a little at the edges, roll in flour, fry in margarine or clarified butter, season with salt and pepper. Take out the leg slices and place in a casserole.
Finely dice the celery, carrots, cloves of garlic and onions, pour off the fat in the pan except for a tablespoon and roast the diced vegetables in it, add tomato paste and roast briefly, deglaze with a dash of red wine and let it boil down while stirring.
Place the contents of the pan with the red wine, bay leaf, marjoram and the meat broth on the leg slices in the casserole. Close the pot and stew at 150 degrees in the oven for 2-2 1/2 hours. When the meat comes off the bone, the dish is done.
Season the sauce to taste. Stir cornstarch into sour cream and use to thicken.