1. Blend all shake ingredients in a high-speed blender for three to five minutes until smooth and creamy.
2. To assemble, shmear a wide strip of hazelnut cream on the outside of the glass, or around the rim, and cover with toasted hazelnuts.
3. Fill your glass with truffle shake and place a cookie over the glass.
4. Top with whipped cream, hazelnut chocolate truffles, melted chocolate, and a chocolate bar.