Lift both sponges out of the baking tin and place them on a flat surface.
Use a sharp knife to level off the top of each sponge so they’re completely flat, and trim the edges of each sponge to make them straight.
Slice each sponge lengthwise to make 2 rectangular strips that are as wide as the cake is thick (mine were 1 inch thick and 1 inch wide). You should now have 2 strips of yellow Pina Colada sponge and 2 strips of pink Raspberry Ripple sponge.
Heat the pineapple jam in a small saucepan on the hob until warm and sticky. Lightly brush the jam onto each long side of the 4 strips of sponge.
Stack and stick the sponges together to make a chequered pattern. If needed, trim the ends to neaten them up.
Dust a large piece of greaseproof paper and rolling pin with icing sugar.
Place the block of marzipan on top of the greaseproof paper and roll into a 25cm(l) x20cm(w) rectangle that’s roughly 0.5cm thick.
Carefully place the Battenberg sponge into the middle of the marzipan and brush the top with jam.
Trim the long edges of the marzipan so that they line up perfectly with the short edges of the sponge.
Now use your hand to wrap the marzipan around the sponge, sealing it together on top. This part is a bit like wrapping a present, just make sure the marzipan is wrapped tightly and use the jam to stick it to the sponge.
Now turn the Battenberg upside down so that the sealed edge is underneath and trim off any excess marzipan.