Spray a 13-by-18-inch rimmed baking sheet with cooking spray. Whisk together the flour and baking powder in a medium bowl.

Grease and line 3 x 20cm/8in round cake tins. For the chocolate sponge, mix together the flour, cocoa, bicarbonate of soda and baking powder in a mixing bowl. Stir in the sugars, orange zest and ...

Preheat the oven to 160C/325F/Gas 3 and grease and line a 24cm/9½in loaf tin or a 20cm/8in cake tin. Weigh the orange pulp and keep 450g/1lb (discard the rest). Place back in food processor with ...