Preheat the oven to 180C/350f. Line the base and sides of two 20cmx20cm square baking tins with baking parchment.
Place the butter, sugar, flour, ground almonds, baking powder, eggs, vanilla and almond extract into the bowl of a stand mixer. Beat, using the whisk attachment, until smooth.
Divide the mixture into two (weigh it out to ensure it's even). Add the almond extract and the yellow food colouring to one bowl and mix together.
Add the pink food colouring to the other bowl and mix. You want a vibrant yellow and pink colour, so add a little more colouring if required.
Spoon one of the mixtures into one tin, and the other into the other tin. Smooth the top and ensure the cake batter is spread into the corners. Place in the oven and and bake for 25-30 mins until an inserted skewer comes out clean.
Allow to cool for 10 minutes in the tin, then transfer to a wire rack to cool completely.
Time to assemble. Roll out one of the marzipan blocks on a surface that's been dusted with LOTS of confectioners' sugar. It needs to be a little more than 20cm wide and long enough to wrap around the cake (about 40cm).
Heat the apricot jam in a small pan (or microwave for a few seconds) until runny.
Take one of the cakes and trim the sides and top so that cooked edges are cut off (you can leave the bottom). Cut the sponge into four long fingers - ensuring the height and width of each finger is equal.
Repeat with the other sponge.
Brush centre of the rolled marzipan with apricot jam (see picture), then lay a yellow sponge finger on top. Brush the side of the yellow sponge, and stick a pink sponge finger to it. Brush the top of the two sponge fingers with jam and place the other two fingers on top (with jam in between those two fingers), so you have a checkerboard effect.
Spread jam on the rest of the marzipan then fold up the sides - making sure it's quite tight, and well adhered to the sponge. Fold the edges back on top of the cake and press them together - like you're sealing a zip-lock bag. Trim the excess marzipan off the top of the cake.
Check again that everything is well adhered, then slice off both ends of the cake - to give a neat finish.
Repeat this process for the other cake.
Turn the cakes over, so the seam is on the bottom, then sprinkle with a little confectioners' sugar and serve.
* If you can't get self-raising flour, replace with a mixture of 2 cups all-purpose mixed with 3 tsp baking powder (see more info here) and also add the other 1 tsp baking powder further down the ingredients list. ** Food colouring Gel/pastes are better than food colouring liquid, as they have a more intense colour that won't fade during baking.Any leftover cake should be wrapped in baking parchment and stored in an airtight box at room temperature. It should keep for 2-3 days..Nutritional Information is per slice.