Melt the Coating Chocolate: Break 12 ounces of dark chocolate into chunks and place them in a bowl over a pot of simmering water (make sure the bowl doesn’t touch the water). Stir until smooth and melted.
12 ounces dark chocolate
Coat the Pan: Pour some of the melted dark chocolate into a silicone loaf pan or parchment-lined loaf pan. Swirl it around or use a spatula to coat the bottom and sides. Drain the extra chocolate back into the bowl. Freeze the pan for 10–15 minutes until the chocolate hardens. Repeat this step one more time for a thicker shell, then freeze again for 10 minutes. Save the rest of the chocolate for the top layer.
Melt the Filling Chocolates: In a clean bowl over the same pot of simmering water, melt the milk chocolate, white chocolate, and the other 3 ½ ounces of dark chocolate. Stir until smooth.
3 ½ ounces white chocolate, 3 ½ ounces dark chocolate, 5 ounces milk chocolate
Add Nutella: Take the melted chocolate off the heat and stir in the Nutella. Keep stirring until it's smooth and creamy.
½ cup Nutella or other hazelnut spread
Add the Hazelnuts: Fold in the toasted hazelnuts until they’re evenly coated in the chocolate mixture.
1 ¾ to 2 cups whole hazelnuts
Fill the Pan: Take the loaf pan out of the freezer and pour in the hazelnut filling. Use a spatula to even it out. Refrigerate for about 30 minutes.
Top with More Chocolate: Pour the remaining melted dark chocolate over the top of the filling. Spread it evenly, cover the pan lightly with foil, and refrigerate for 3 to 6 hours, or until firm.
Slice and Serve: Once it’s firm, take the nougat out of the pan. Let it sit at room temp for about 15 minutes before slicing if it's super firm. Cut into thick slices or big chunks—because portion control is just a suggestion.