Cut out 2 circles of greaseproof paper, one 4" in diameter and one 2" in diameter.
Place the larger template in the middle of one of the sponge cakes and cut round it. Repeat on the other cake.
Place the smaller template in the middle of the cake and cut round it. Do the same on the other cake.
Carefully lift the outer ring of one of the sponge cakes and place onto a cake board.
Spread some of the apricot jam onto the inside of the cake ring.
Take the inner ring of the other coloured cake and place inside.
Coat the inside with apricot jam.
Place the inner circle of the opposite coloured sponge in the middle. You should have alternating colours of sponge cake.
Spread a layer of apricot jam over the bottom layer of the cake.
Repeat the process for the top layer of the cake and then decorate it. A traditional battenberg should be covered with marzipan, but I used a thin covering of icing.
When you cut a slice out of the cake, the squares are revealed.