Melt 30g margarine. Heat 35g wheat flour in it, stirring, until it is light yellow. Pour in 500ml instant meat stock, beat through with a whisk, making sure that no lumps are formed. Stir in 1 tablespoon capers, bring the sauce to a boil, cook for about 10 minutes.
1 egg yolk with 2 tablespoon. Beat in cold water, peel off the sauce, season with salt, lemon juice or 2 tablespoon white wine.