MK - I love the strawberry cream cheese cupcake at BOG. I also love love love the big chocolate covered Mickey apples at the Confectionary and Big Top Sweets.
Epcot - School Bread, and everything I've tried at Les Halles Boulangerie Patisserie in France.
HS - The carrot cake cookie sandwich. I can't remember where I got it, though! It was big enough for at least 2 people, and so fresh and delicious!
AK - I love the blueberry cream cheese dessert at Satuli Canteen. It was unique, and so good!
DS - Last summer I had a S'mores Crepe at Aristocrepes. I couldn't finish this, it was gigantic, but so good. A little hot, I couldn't eat it for a few minutes, but amazing still.
And at all of the above - Mickey ice cream bars! I had my first one last summer and I could not believe how good they are! I have almost one per day now!