Battenburg cake - your foolproof recipes please.....

[whojamaflip]

So it's our local agricultural show on Saturday and the lovely ladies in our village issued a challenge to enter the battenburg cake class.

I've tried several times today to make the sponge and every single bloody time it's sunk when I've taken it out of the oven. Please can any of you clever bakers let me have a foolproof recipe which I can make tomorrow to rescue me from a seriously embarrassing incident? I've managed to make the marzipan, it's just the sponge that I'm struggling with and I'm usually a competent baker

I use this link recipe and it usually turns out well x

this is Mary berry's recipe. I've found it to be foolproof. Good luck!

Thankyou - I used Mary Berrys recipe and ended up making 3!! To get enough risen bits to cobble together

It's looks like a battenburg but the marzipan is bit like crazy paving - dropped it off at the show last night and to be fair it wasn't the worst looking one but there were some seriously professional looking entries!!

As long as it doesn't fall apart when (if!!) they cut it today I shall be happy