Pre-heat your oven to 150C Fan/165C/325F/Gas Mark 3
Line an 8" square tin with a layer of foil covered with a layer of baking paper. Fold a crease about 3" tall in the centre of the paper to stop the two sponges from joining up
Make the sponge by mixing the butter and caster sugar in a large bowl with an electric mixer, or in a stand mixer for until fluffy. You can also mix by hand, but an electric mixer will give the best results
Add the eggs and vanilla extract, and whisk until fully incorporated, again using an electric mixer
Gently whisk in the self raising flour using a hand whisk, and whisk in until you can't see any flour anymore
Split the batter in half and gently stir pink food colouring into one half of the batter until a light pink shade is achieved
Pour the pink batter into one half of the tin, and the uncoloured batter into the other half
Bake for 35-40 minutes or until a skewer inserted in the middle comes out clean. Leave it to fully cool either in the tin or remove from the tin and place on a cooling rack
Trim the golden crusts off both colours of cake and then cut into long rectangular strips. Use a ruler for accuracy
Warm the apricot jam for 30 seconds in the microwave, then put it through a fine sieve
Dust your work surface with icing sugar and roll out the marzipan onto it. Aim for a rectangle around 12" x 8" - it must be long enough to wrap around the cake
Brush the marzipan with the apricot jam, then assemble the cake in the centre of the marzipan in a checkerboard pattern, brushing apricot jam between each cake
Wrap the cake with the marzipan, let the marzipan overlap slightly and trim the rest off
Trim the edges of the marzipan too, and then flip the cake over so the seal is on the bottom
Use a cake decorating brush to brush off any icing sugar, then the cake is ready to serve!
Serve immediately, store any leftover in an airtight container in a cool place and eat within 3 days. The marzipan will go sticky after a day or so