1 – Break the chocolate into small pieces and melt it in a double boiler with a tablespoon of water. Chop the truffle finely and set aside.
Pour the liquid cream into a saucepan and bring to a boil.
At the first boil, remove from heat and pour in 3 times on the chocolate while mixing with a whisk, then add the butter in small pieces.
2 – Add the truffle and hazelnut slivers, then mix until the mixture is smooth.
Let cool to room temperature: cover and place in refrigerator for at least 6 hours.
3 – Once the ganache has cooled, pour the hazelnut powder into a soup plate, add grated chocolate beforehand.
Form small balls and roll them in the chocolate hazelnut powder.
Keep chilled until ready to serve.