In a small bowl, mix together beef broth, flour, tomato paste and demi glace; set aside.
Heat bacon drippings in a large heavy skillet over medium heat. Add beef, and cook until brown on all sides. Remove beef from skillet; set aside. Stir the sherry wine into the skillet. Add the onions, and cook about 5 minutes. Blend in the tomato paste mixture, and bring to a rapid boil, stirring constantly. Stir in Burgundy wine. Make the herb bouquet: Place parsley, rosemary, thyme, and bay leaf in a square of cheesecloth. Place herb bouquet in sauce.
Return beef to skillet. Cover, and simmer over low heat for about 3 hours, or until beef is tender.
Melt butter in a small skillet over medium heat. Saute mushrooms until lightly browned. Add to meat in the skillet, and continue cooking 15 minutes. Discard bouquet garni. Serve in a casserole dish, sprinkled with parsley.