Does anyone know if marble cake can be adapted for a rectangular shaped cake? any recipe I've ever made with marble cake (& all the ones I've looked at today to find something different) say it has to be baked in a round pan. Is this true? I've only ever made it in a round pan but a friend wants a marble cake with a shape that requires I make it in a rectangular shaped pan ( a bottle laying flat) and I'm worried that it won't work. If anyone can help me out I'd appreciate it. Thanks
(I'd be using a 12 inch rectangle)

Ah ok, thanks. I didn't think so but then got confused by everything I had read - case of reading too much.
I have another question though (just thought of it or else I would have put it with the first question), marble cake tends to be very light and airy do you think it can hold up under bc and mmf? it will be a bottle lying down so gravity should not be a problem but do you think it will 'sink' with the weight?

No. It shouldn't sink. If your cake is taller than two 2" layers (or more than 4" tall), then you'd need to use a support system.

Thanks! Just put it in the oven.