Prepare the rolling pin.
Wrap a sheet of waxed paper around your rolling pin. Attach the paper to the rolling pin with scotch tape, or place rubber bands on both ends of the rolling pin to keep the paper down. Prepare a surface underneath with a large sheet of waxed paper to catch any dripping chocolate.
Make the curls. Scoop up some melted chocolate using a ladle, a large spoon, or a cup. Or pour into a pastry bag for greater precision. Pour a small amount of the chocolate slowly onto the rolling pin. Continue to drip the chocolate along the rolling pin in a zig-zag motion.
Let the chocolate sit on the rolling pin until almost hardened.
Leave to set. Carefully remove the chocolate from the rolling pin. Place onto a dish covered in waxed paper and place the dish in the fridge or freezer until set. Use immediately, or store in a ziploc bag in the freezer until needed.
The vegetable peeler method:
Find a slab of good quality chocolate. 50%-70% cacao will do. You may need to chill the chocolate for several hours in the refrigerator before shaving. <- VERY IMPORTANT! If you try to use room temperature chocolate for chocolate curls you will end up with thick, broken, chunky pieces of chocolate instead of thin, delicate shavings.
You can find wrapped blocks of chocolate at most grocery and specialty stores. Regular bars of chocolate will not work as they are too soft.
You will want to master the peeling technique. Hold the bar of chocolate in one hand — you may want to hold it in a piece of paper towel to stop the bar from melting in your hand. Slowly and carefully, use the peeler to shave along the length of the bar to form pretty chocolate curls.
Pressing the peeler deeper into the chocolate will result in bigger, more dramatic curls, while drawing it gently across the edges will produce smaller, more delicate curls.