I have 3 favorites!
Kiluea Torte at Kona Cafe @ the Poly - a dark chocolate flourless cake with a warm, gooey chocolate and hazelnut center. Incredible!!!!
Banana Napoleon at Flying Fish @ The Boardwalk - layers of phylo, cream, and bananas. I think there is caramel drizzled over the entire masterpiece!
Berry Cobbler at Artist Point @ Wilderness Lodge - loads of fresh berries (blueberries, raspberries, blackberries, whatever they have available), served over a golden cake with whipped cream. Lovely! And enough for 2 or more to share.