Preheat oven to 170°C. Spread the hazelnuts over a baking tray and cook in preheated oven for 5-6 minutes or until toasted. Place hazelnuts in a tea towel and rub to remove the skin. Finely chop the hazelnuts and place in a small bowl. Set aside.
Heat the cream and orange peel in a small saucepan over medium-high heat until it just comes to the boil. Remove from the heat and set aside for 10 minutes.
Place the chocolate in a medium bowl. Return the cream to medium-high heat and bring to the boil. Discard the peel and pour the cream through a sieve over the chocolate. Stir until the chocolate melts and the mixture is smooth. Add the whisky and stir to combine. Place in the fridge for 1 hour or until firm.
Line a large tray with non-stick baking paper. Spoon teaspoonsful of the mixture onto the lined tray. Place in the fridge for 5-10 minutes to firm.
Lightly press the mixture into balls. Place the cocoa in a small bowl. Roll 1/2 the truffles in the cocoa and the other 1/2 in the hazelnuts. Place in the fridge for at least 15 minutes before serving.
