Preheat oven. Preheat oven to 180 degrees celsius and line a baking tray with baking paper.
Roast Hazelnuts. Once the oven has heated, place the hazelnuts in a single layer on the baking tray and bake for about 5 to 8 minutes until the skins have darkened and are easy to remove. Rub the hazelnuts between your hands or in a tea towel to remove as much of the skins as possible. Don't stress if you cant get all the skin off. If you can find blanched hazelnuts even better.
Make truffles. Place the hazelnuts into a high-speed blender and process until they form a smooth paste. Add in all of the other ingredients and process until combined and smooth. Place the mixture in a bowl and place in the freezer to firm up, approximately 1 hour.
Coat in cacao powder. Remove from the freezer and roll into small balls and then coat in the cacao powder. Place back in the freezer until ready to eat, approximately 1 hour.
Notes
If you can find blanched hazelnuts, then once you roast them, then allow to cool slightly before moving onto the making the truffles.
Store in an airtight container in the freezer and remove 5 minutes before eating.
The cook time does not include the time it takes for the truffles to set in the freezer.