Stuffing: To prepare stuffing, dice bacon and onion. Cook bacon in a frypan until partially cooked; add onion and cook for 5 minutes. Drain and chop mushrooms, add to frypan and cook for another 5 minutes. Remove mixture from heat, let cool and transfer to a mixing bowl. Add herbs, ground beef, bread crumbs, eggs, and sour cream. Mix thoroughly. Season with salt and pepper. Veal: With a sharp knife, cut a pocket in the veal breast or leg. Fill with stuffing; close opening with toothpicks. (Tie with string if necessary.) Rub outside with salt and pepper. Heat oil in a Dutch oven. Place meat in the pan and bake in a preheated 180ºC . oven about 1.5 hours. Bast occasionally with beef broth. When done, place meat on a preheated platter. Pour rest of beef broth into the Dutch oven and scrape brown particles from the bottom. Bring pan drippings to a simmer. Thoroughly blend cornstarch with sour cream and add to pan drippings while stirring cook and stir until thick and bubbly. Slice veal breast and serve sauce separately.