Mince the meat very finely. Finely chop the onion, heat the fat and fry the onion until lightly browned, then add the flour and fry lightly. Put in the minced meat and cook lightly. Add the stock or water, seasoning and the mushroom ketchup, lemon juice or vinegar. Cook very gently for 20 min., stirring occasionally. Then serve on a hot dish and garnish with sippets of toasted bread and parsley.