Warning:  Contains SOYA For a soya-free version, please see Cook’s Notes at the bottom of the recipe Ingredients: 150g gluten-free plain white flour 1 tbsp gluten substitute 1 tsp bicarbonate of soda 1 tsp cream of tartar 3 eggs’ worth of egg replacer 150g caster sugar 30g cocoa powder 180g dairy-free margarine, softened 80g soya…