MK: Head to Big Top Treats and have them slice up one of the chocolate caramel apples. It's really fun to share!
AK: I'm not a big fan of their food/snacks... maybe I'm missing something? I guess this might be the place to suggest some treats you can get almost anywhere, like a Mickey Bar and a Dole Whip!
HS: Carrot Cake Cookie (more like a whoopie pie) at Sweet Spells, the Butterfinger Cupcake (the best cupcake in the entire world) at Trolley Car Cafe. I believe it has a different name now, though - something like Peanut Butter Crunch Cupcake?
Epcot: Anything at Karamell Kuche in Germany and the Cronut (crossaint donut) at Refreshment Port just outside of Canada. Les Halles Boulangerie in France has some hits for us, like the almond croissant, pain au chocolat, lobster bisque, and a cheese and bacon roll I can't remember the name of. We also enjoyed Kakigori with sweet milk topping in Japan, but then again, it's just shaved ice. If you're willing to duck out of Epcot for a quick stop, go to Ample Hills Creamery at the Boardwalk for a seriously amazing sundae.