Heat the margarine in a frying pan and gently brown the chopped onions. Sprinkle with flour and allow to take color. Add the broth, add the tomato paste and the bouquet garni. Season with salt, pepper, cover and let simmer for 20 minutes over low heat.
Cut the beef into thin slices. Pour half of the onion sauce into a baking dish. Arrange the meat slices and cover with the remaining sauce.
Sprinkle with chopped parsley, pour vinegar and sprinkle with breadcrumbs. Fry for 20 minutes in a medium oven (tea 6, 180 °).
Serve with a green salad.