Gum paste recipe No 2 By clomo recipe Comments | 0 Favorites | 236 Another recipe for Gum Paste, from an old cake decorating book of my grandmothers. Gum paste recipe No 2 Ingredients 1/4 oz gelatine (one envelope)1/2 cup water1 level teaspoon cream of tartar4 cups icing sugar1 cup cornflour Instructions Place first three ingredients on a low heat and stir. When dissolved, add pure icing sugar and cornflour. Knead it like pie dough until smooth. Cover with a damp cloth.