Line a 12-hole muffin tin with paper muffin cases. Sift the flours and baking powder into a large bowl. Stir in the sugar, ginger and cranberries until evenly distributed.
Beat together the egg, milk and oil in a separate bowl, then add the liquid to the flour mixture. Using a large metal spoon, gently stir the liquid into the flour, until only just combined. The mixture should look craggy, with specks of flour still visible.
Divide the mixture between the muffin cases, piling it up in the centre. Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 18–20 minutes, until well risen and golden. Transfer to a wire rack and serve while still slightly warm.