Add salt and pepper the meat. Fry the in a roasting pan on all sides until golden brown. Pour the vegetable or meat broth. Add coarsely chopped roots and bay leaf and cook for 2 hours on low heat. Remove meat from broth and cut into slices 1.5 centimeters thick. Broth. For the sauce, chop the onion into strips, fry gently in butter until transparent. Add mustard, salt, sugar and vinegar, podpylit flour and pour the broth, to interfere, to avoid lumps and cook for 20 minutes. Season. Put the meat in the sauce, and serve warm.