Using an electric mixer, cream together the butter and sugar. Add the egg and lemon zest and mix until combined. Stir in the flour, baking powder and Kellogg’s Two Scoops Raisin Bran mixture and mix again until combined. Spoon the batter into the prepared cake pan and bake in the centre of the oven until a toothpick inserted into the cake comes out clean. Remove cake from the oven and place it on a wire rack to cool.