Hi everyone, im just wondering how everyone scales up recipes to suit different tiers. Fruit cakes are fine, i have loads of receipes for them but I can't find chocolate cakes and sponge cakes that can be adapted to different tiers. i can find different individual receipes for different tiers but i really want to find ONE choc cake and ONE sponge that i can use for my failsafe cakes rather than use different recipes depending on size. Can anyone help?

I do just scale up, but it's not just a total gross up of each ingredient. It's explained pretty well in the Cake Bible (book.)