Would greek yogurt work instead of buttermilk?
I don't know the answer but what's the recipe for the cake ? :)
http://www.allotments4all.co.uk/smf/index.php/topic,20515.0.html (http://www.allotments4all.co.uk/smf/index.php/topic,20515.0.html)
Just noticed on that link E-J says that she used milk instead of buttermilk or yogurt, so guess that answers my question!
That sounds like it will also work with the bramley apples the blossom is promising a bountiful harvest from on me tree.....
Just to let you know, it worked out fine, but also to advise using a lined, loose-bottomed tin, as it's quite a sticky cake and you can't tuen it upside down or all the topping falls off!
If you want it more cake like ..you could use set yogurt/Greek yogurt instead and add 1/2 cup of more flour...it should still be moist ;D