cake mishap

[chrissy]

I wondered if anyone has any ideas where i went wrong, i made the castle cake to a carol deacon light maderia recipie, i thought i had found a great easy recipie, the 4 inch top was perfect, also the chocolate.
when we cut into the bottom which is 2 layers of a 7 inch square, to make deeper. there is all the way running through the cake like a darker band........ the cake is cooked, but looks a bit like a thick marbly line? looks horrible, where did i go wrong?
she did want to take a lot to work for her friends, but i cannot let it go out looking like that it looks horrible.

[emmascakes.co.uk]

If it's two cakes on top of each other isn't the dark line just the top of the cake that's at the bottom of the stack?

[rach]

yep if it was two sponges it would be the cooked outside showing...if stacking two cakes to make one deep one trim off the outside so it looks more even and also fill it with whatever filling you are using then it wont look so obivious....