Usually only seen in the professional kitchen, feuilletine (foo-ye-teen, more-or-less, from the French “feuille,” meaning “leaves”) tastes like crispy, thin little shards of sugar cone. You can mix it in to mousses to add some crunch.
Mix into ganache and use for truffle centers. One of the keenest (?) uses is to mix it in to tempered chocolate to just barely coat it, spread it out thinly on silpat, let cool, then break up and use like crispy chocolate tuiles. Oh, my.
To purchase by the box, click on the word feuilletine above, or substitute slightly crushed Corn Flakes or Rice Krispies. Seriously.
If you’re feeling Snazzy, The Brave Tart has a recipe up. Yes, you can make it yourself after all (although it might not be quite as ethereally thin and crisp as purchased, it will still be several cuts above using cereal)!
You can also make Crepes Dentelle and crush them up for feuilletine.