Low Carb Battenberg Cake

Method

1. To make the marzipan: In a medium-sized bowl or mixer, add the ground almonds and icing sugar substitute. Mix until well combined.
2. Add the egg white and almond extract and knead the mixture until it is smooth and easily forms a ball. It should be slightly moist and sticky in texture.
3. Cover the marzipan with cling film and set aside whilst you bake the cake.
4. To make the cake: Preheat the oven to 350℉ / 180℃ / Gas mark 4. Grease and line a Battenberg tin with baking paper. If you do not have a Battenberg tin, then grease and line a 20cm square cake tin. Divide the square tin into two sections with foil that has been folded into a thick piece.
5. Beat the egg yolks, half of the sweetener and the vanilla extract together in a large bowl until smooth. Set aside.
6. Whip the egg whites in a mixer, if you have one, until soft peaks form. Once the soft peaks have formed slowly beat in the other half of the sweetener.
7. In a separate bowl, mix together the flour, baking powder, and salt. Break down any lumps, then add the dry mixture to the egg yolks and stir to form a thick dough.
8. Fold the egg whites into the dough, 1-2 spoonfuls at a time. The end result should be a smooth and fluffy batter.
9. Pour half of the batter into a separate bowl, add a drop of pink food colouring and stir. Add as many drops as needed to get the right colouring. I used 3 drops in mine. Stir until fully combined.
10. If using a Battenberg tin: Pour the plain batter into two of the strips in the tin. Pour the pink batter into the two other remaining strips in the tin.
    
    If using a square cake tin: Pour the pink batter in one half and the plain in the other half, making sure to hold the foil in place to keep the mixtures separated. Bake in the oven for 30-35 minutes, until the plain cake is golden brown and a toothpick inserted into the cake comes out clean.
11. Remove the cake from the oven and allow it to cool for 5-10 minutes. Run a knife around the edge of the tin and between each strip to loosen the strips of cake. If you used a square cake tin, when the cakes have cooled, cut both halves in half to make 4 strips of cake (2 pink and 2 plain). Place the strips of cake onto a cooling rack and leave to cool.
12. To assemble the cake: Take one pink strip and one plain strip. Spread the jam across one side of the pink cake strip and firmly stick it to one side of the plain cake strip. Spread jam on top of these two strips and firmly place the remaining strips on top, making sure to alternate the colours. For example, place a pink cake strip on top of the plain cake strip.
13. Place the marzipan between two sheets of parchment paper and press down to flatten slightly with your hand. With a rolling pin, roll the marzipan out to about 1cm of thickness, checking that it is long and wide enough to wrap around the cake. You can do this by placing the cake on top and seeing if the marzipan will wrap around the cake.
14. Once the size is right, spread jam over the long sides of the cake where the marzipan will wrap around. Place the cake in the middle of the flattened marzipan and wrap the marzipan tightly around the cake. Smooth over the joins with your fingers. Turn the cake over so the joining is underneath.
15. Cut the excess marzipan off either side of the cake. I also cut off a small slice of the sponge on each end to form straight edges. If the marzipan is not tight enough around the sponge cake, wrap the cake in clingfilm and gently push down on each side of the cake to mould the marzipan onto the sponge cake.
16. Serve immediately or store in a tin for up to 3 days.