Careful. There are two versions of the Slipper - one available only at CRT, and the other available at any Grand Floridian restaurant.
You need to order it at least 48 hours in advance, and you may not be able to get the "other" one, i.e. the one not normally served at your restaurant of choice.
ETA: It's not covered by any Dining Plan credit - you need to pay for it.