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asked September 8th 2012

Sponge sizes for 100

I have been asked to do a sponge cake for a party but it needs to do at least 100, the cake is for a plumber and after looking on the internet I was asked to do the kitchen sink unit with the plumbers bum sticking out from under the sink. At first I planned to do this on top of a square cake but now think it might look a little odd, I suggested I could do an additional cake for just cutting and serving behind the scenes then wondered if I should use two big square cakes side by side for the units (would have to be reasonably high) but it seems cake boards for such sizes are extortionate.
I don’t want the main cake to be too small as people like to think they are getting a piece of the actual birthday cake so now wondered if I should do kitchen units around a corner as well, I am just not sure how much cake I will need.
Any ideas on how to do this would be appreciated.


Hi cat71,

I have never done this type of cake before, however, here are some portion sizes for sponge cake, I hope this helps:

round 6 inch serves 14
round 8 inch serves 25
round 10 inch serves 39
round 12 inch serves 56

square 6 inch serves 18
square 8 inch serves 32
square 10 inch serves 50
square 12 inch serves 72

these are approximate measures and are for sponge cake only.
If you did a 12 inch and an 8 inch square and cut them in half and stacked on half on top of the other you would have two tall rectangles that would feed approx 104 people, Put them into an L shape and they should fit on a 12 inch board.,maybe that would do?

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