If you have a solid block of chocolate, simply use a vegetable peeler to peel off curls, allowing them to fall gently onto a plate or piece of waxed paper in a single layer. (If you get only shavings, try warming the chocolate just slightly.)
Otherwise, begin by melting chocolate chips, chocolate confectionery coating or chocolate bars. (The amount used depends on the number of curls needed.)
Pour the melted chocolate onto the back of an inverted cookie sheet and spread to a smooth, thin layer. Let cool until firm and pliable but not brittle.
With a cheese slicer, metal spatula or pancake turner, scrape up a thin layer of chocolate using even pressure. The chocolate with curl as you go. The slower you scrape, the wider your curls will be.
Slide a toothpick or wooden skewer through each curl to carefully lift it onth the cake and arrange as desired.