Put the oat flakes in a mixing bowl, pour the water over them and soak for about 5 minutes. Peel the onion and chop it very finely. Finely grind the walnuts. Add the onion, walnut oil, tomato paste, mustard, broth, walnuts, margarine and lemon juice to the oatmeal. Mix everything into a cream and pour into a bowl for serving.
By the way: Whole grain oat flakes are said to have a cholesterol-lowering effect.