In a food processor, pulse the hazelnuts until finely chopped.
Melt dark chocolate and coconut oil in a small saucepan over low heat, stirring occasionally.
Add maple syrup, vanilla extract, and sea salt to the melted chocolate mixture.
Stir in the chopped hazelnuts until the mixture is well combined.
Let the mixture cool slightly before placing it in the fridge for 15 minutes.
Once chilled, scoop out small portions and roll them into truffles.
Roll each truffle in cocoa powder for an extra touch of indulgence.
Chill the truffles again for at least 30 minutes before serving.
Enjoy (or hide them from the rest of your family).