Hi Ann Marie,
I love celebrating birthdays at Disney World! You have a couple of choices for cakes. There are smaller cakes shaped like Mickey that are available at most table service restaurants. All you have to do is request it when you check in for your reservation. They are cute and tasty!
If you would like to look into having a custom cake made for your boyfriend you can call Disney's cake line at (407)827-2253. They will guide you through choices, give you ideas and, of course, answer your pricing questions. They will need a few days advance notice.
Also, don't forget to go to Guest Services at whichever Park you are in that day and ask for a Birthday button. They are complimentary and he'll get happy birthday wishes from all of the Castmembers throughout the Park. For other ideas please visit,
www.waltdisneyworld.com and type "birthday celebrations" in your Search engine. You'll be surprised at how much is offered that you can take advantage of.
Wish him a happy birthday from me! Have a great time.