Using a melon baller or small ice cream scoop, spoon out balls from the tray of tiramisu to create the bon bons. Freeze the bon bons on a cookie sheet for at least 1 hour or overnight.
Melt the bittersweet chocolate in a double boiler until smooth and glossy. Dip frozen tiramisu bon bons in melted chocolate until covered on all sides. Place the bon bons on a cookie sheet covered in parchment or waxed paper and return them to the freezer. Take bon bons out of freezer and let them thaw for about 15 minutes before serving.
Recipe courtesy of Michael Chiarello