I wouldn't have put pre-packaged items into my list until I saw people listing the cookies and what I want to dub, "Mickey Mounds Bars". Except when you put "Mickey" in front of "Mounds", well it sounds kinda gross. But I digress!
My pre-packaged item I tend to buy for my quick consumption at home:
The "Chocolate Chocolate" hot cocoa mix that comes in that oval cylinder tin. They have other flavors, but that's the only flavor I get. Love it.
As for the other stuff, I don't always go to the same restaurants each time, so I can't put a specific menu item. (Although I do always get that mushroom soup at Artist Point! Mmm!)
So I guess that leaves...
The Dole Whip. I tend to get one each trip, regardless.
I tend to get that more than churros, my other snack of choice in the MK.
And if I'm going to blather on about park specific items, I might as well continue...
Epcot:
I don't have a MUST for each trip. But I wouldn't say no to fish and chips, one of the specialty drinks around World Showcase, or Beverly. Yes,
Beverly. I drink it because I
can. Without any ill effects. I seem to be immune to the "ick factor". I'm the perfect shill to trick the unsuspecting into taking a swig. I am slightly evil.
Studios:
Nothing here thrills me, snack wise. I tend to get a Mickey bar.
AK:
I once had pot stickers (pre-Yak and Yeti) in Anandapur, and I thought they were great. I haven't tried to find them since, but I liked them.
