Yes, for sure, most Disney Sit Down restaurants can get a specially prepaired cake to help you with your celebration.
Call the restaurant direct and order thru them.
They will need a minimum 48 Hours before your PS.
The cakes are a little pricey (min. around $40) but they will ask you for you choice cake, filling and frosting, colors and inscription.
Most every cake I have had at Disney have been out of this world!