Cornflour is the starch extracted from maize which is soaked and ground to separate the germ and the bran. It contains no gluten. A fine white powder with no taste, it is used to thicken sauces. It cuts down the need for fat as, unlike other flours, it blends to a smooth cream with liquid. To use, blend with double the amount of cold liquid to cornflour and stir into sauce to be thickened. Keep stirring while the sauce comes to the boil, and it will clear and thicken.