Ahoy, Cynthia!
It sounds like your granddaughter has paid a visit to
Be Our Guest Restaurant in Walt Disney World Resort's
Magic Kingdom! The "grey stuff" is a featured treat at Beast's castle, and a favorite among guests. First offered as a celebration dessert, the grey stuff now tops the Master's Cupcake - my dessert choice at any meal at Be Our Guest. It's delicious! Don't believe me, ask the dishes!
Here's a little secret: the "grey stuff" is actually cookies and cream flavored mousse. While not offered by itself on the
Disney Fantasy, you can find an Oreo Cupcake in Disney Fantasy's sweet shop,
Sweet On You. The frosting is almost identical to the grey stuff. I'm not sure if you could order a "frosting only" version of the cupcake, but you could always ask! They also serve Cookies and Cream ice cream, and a delicious Cookies and Cream specialty milkshake. My family was on the Disney Fantasy in November, and I also seem to remember a few cookies-and-cream flavored desserts offered throughout the cruise.
I hope you and your granddaughter have a magical voyage on the gorgeous Disney Fantasy, and that she feels like the "Belle" of the ball from beginning to end! - Diane W.