I have been asked to make a Barbie cake by a co-worker.
How many servings should she expect to get from the cake ?
She is expecting 40 people and I already told her she would need
another sheet cake but what size? Thanks for the help

There are several sizes of 'doll skirt' pans. If you use one mix/recipe it will serve approx. 12-15. If you use 2 mixes double that. What you can do to bring in the additional servings is bake a round or petal cake to put under the skirt cake increasing the height of the cake - that also will make the doll fit better - if you are using a 'real' Barbie doll.
Once the skirt cake is baked you will have to enlarge the center hole to fit her hips in. Be careful to do this so it does not crack the whole cake - which will happen if you just force her in.