In a heat-proof bowl set over a pot of simmering water, add the chopped chocolate, heavy cream, and butter. Heat until melted and combined, stirring frequently. Remove from heat when most chocolate is melted but a few small chunks remain. Continue to stir off heat until smooth.
Stir in chocolate-hazelnut spread.
Chill in the fridge for 2-3 hours until firm and scoop-able. You can speed this process up by placing in the freezer for 30 minutes, then transferring to the fridge.
Use a tablespoon to scoop and portion chocolate, and roll in your hands to form a ball. Wipe hands clean in between every few truffles as needed.
Roll in crushed hazelnuts.
Store in the fridge until ready to serve. Truffles will keep for a week or more.
Calories: 172kcal, Carbohydrates: 13g, Protein: 2g, Fat: 13g, Saturated Fat: 7g, Cholesterol: 9mg, Sodium: 16mg, Potassium: 136mg, Fiber: 2g, Sugar: 10g, Vitamin A: 102IU, Vitamin C: 1mg, Calcium: 27mg, Iron: 1mg