Welcome to the Cake Decorators Q&A

asked February 24th 2019

Half dome sizing and oil based recipe

Hi, I’ve been lent a half sphere cake tin which I’m going to use for the Huddle Cake. Can anyone tell me how to convert the sponge cake recipe to size....it’s 8” stars the widest.

Also I need to make it several days in advance and it’s been suggested that an oil based recipe would help keep it moist. I’m doing a lemon sponge. Do you know if any good foolproof recipes please?

Thank you!


*stars?!? 8” at the widest


Hi therese1

Assuming the recipe for an eight-inch round cake produces a depth of three inches, to convert this to a hemisphere you need to reduce all the ingredients by one third. To get the amount of ingredient required simply multiply each value by 66% or 0.66.

Take a peek here as well for another explanation:


Unfortunately, I am not able to recommend an oil based sponge recipe. I have searched in google and have seen several which might be ok. As I understand it, liquid fat can be used in the same quantity as solid fats. However, the mixing methods would be different. You would need to foam together the oil, eggs, sugar and flavouring to a creamy thick state and then add the flour gently, in two or three stages until combined. My advice would be to make a trial cake to test the texture. Alternatively, you could substitute some of the oil for butter to make a sturdier cake.

Please let me know if this makes sense 🙂

ps. there are several other comments pertaining to hemisphere cake tins here:
There are several pages, scroll down to see them.