Preheat oven to 175°C and prepare a 9"x9" pan by greasing it with butter or oil and making a foil strip down the middle to divide the pan into two equal portions.

Cream together butter and sugar until soft and fluffy, then add the egg white and eggs, stirring just to combine.

Add to this the vanilla extract, baking powder, salt, oil, and flour and mix sparingly.

Divide the batter into two bowls: to one add the lemon juice (and lemon extract or lemon zest if you want), to the other add 2-3 tablespoons of the raspberry jam and mix both until there are no streaks.

Pour the lemon batter into one side of the aluminum divider and the raspberry on the other, making sure that they do not leak into each other.

Bake for 25 minutes or until a toothpick comes out clean and the cakes just start to color on the top, cool the cakes completely before assembling.

Trim each cake to be the same size then divide in half to form two pieces of each flavor, four pieces in total.

Lightly paint each side of the cake strips with raspberry jam then, place one raspberry piece next to one lemon piece and top with the other lemon and raspberry piece to make a checkerboard pattern.

Dust a flat surface with confectioner’s sugar and roll out marzipan to a 8×12-inch rectangle, then place the stacked cakes along the rolled marzipan and pull the marzipan closed around the cake and seal the edges, smoothing the seem as you go. Cut any excess, score the top and decorate if desired.