Two suggestions, based on your likes.
Get the chocolate peanut butter pie from the contempo cafe at the contemporary. We stayed at bay lake once, and I got it three times that week.
Also, more of a tip, than a suggestion, but I love to get an ice cream cookie sandwich from the Plaza Ice Cream shop on main street. It is made to order, so you can order any ice cream flavor. And the cookies are fresh, sometimes warm. Here is the tip, though, you can add a cup of peanut butter dipping sauce on the side for less than a dollar. Its warm, too. You dip your ice cream sandwich in that and you're livin'.