In the same pan, brown the onions and mushrooms. Add oil, if needed. Add the garlic, mustard and cook gently for about 1 minute. Return the meat to the pan and add the broth and sauce. Bring to a boil. Cover and bake for about 2 hours and 30 minutes. Remove the cover and continue cooking for about 30 minutes or until the meat is fork tender. Add the parsley and adjust the seasoning.