Ingredients: 2 pounds round steak or sirloin tip 3-4 Tablespoons butter, margarine or olive oil 6 medium onions, chopped 1/4 teaspoon marjoram pinch of thyme 1 clove garlic, chopped 4 Tablespoons vinegar 1 cup water or beef stock 3 Tablespoons flour dissolved in a little cold water strip of lemon peel salt and pepper
Directions: The meat should be cut into thin leaf-like strips. Heat fat in 2 quart pot and fry onions slowly, stirring until deep yellow but not quite brown. Add meat, salt, pepper, marjoram, garlic, thyme, vinegar, lemon peel and 1/2 cup water. Cover and simmer slowly but steadily for 1/2 hour, adding more water if needed as meat cooks. When meat is tender, dissolve flour in just enough cold water to make a smooth paste and stir into gravy. Check seasoning and add more salt and pepper if needed. Serve over noodles or rice.
Source: http://www.sheries-kitchen.com/recipes/german/zwiebelfleisch.htm