Wipe and trim the meat, removing any skin and fat. Cut into neat pieces. Heat the fat and sauté the sliced onions with the meat, until the meat is evenly browned. Add the flour and stir until brown. Then add the stock, wine, skinned and diced tomatoes, salt, paprika, and bouquet garni. Stir, bring to the boil. If liked, transfer to a casserole and cook slowly for 1½–2 hr. in the oven, stirring occasionally, or continue cooking in saucepan for the same time. Add the diced potatoes about ½ hr. before the goulash is ready. They should be cooked but not broken. If liked, 2 tablesp. sour cream may be stirred in before serving.