You could be referring to Beaches and Cream at the Beach Club Resort. Place is tiny, but has great food (burgers, fries and such) and great ice cream sundaes, including the "kitchen sink", which is huge and should be shared with 10 of your closest friends or family.
The restaurant does not take ADRs and can pretty crowded at meal times. I would go at opening, about 11am or later in the day, after dinner.