1.Preheat oven to moderate, 180°C (160°C fan-forced). Place hazelnuts in a shallow baking dish, bake in a moderate oven for about 8 minutes or until the skins begin to split and nuts are toasted. Place nuts in a clean tea towel and rub vigorously to remove the skins. Chop nuts coarsely. Bring milk, cream and hazelnuts to the boil in a medium saucepan, cover and remove from heat.
2.Whisk the egg yolks and sugar in a medium bowl until creamy. Gradually whisk hot milk mixture into the egg mixture. Return to the saucepan, stir over low heat, without boiling, until mixture thickens slightly and coats the back of a spoon. Run a finger through the custard on the back of the spoon – it should hold its shape. Add the chocolate hazelnut spread; whisk until combined.
3.Transfer to a large jug or bowl, press plastic wrap over surface of custard; cool slightly, then refrigerate for 2 hours or until cold. Strain mixture into a jug to remove hazelnuts. Pour mixture into an ice-cream maker; churn following the manufacturer’s instructions until firm.
4.Or, transfer the mixture to a shallow container, cover with foil and freeze until almost firm. Chop the ice-cream coarsely; place ice-cream in a large bowl. Using an electric mixer, beat ice-cream until smooth. Pour into a deep container, cover and freeze until firm. Serve scooped in cones, if desired.
This recipe can be made up to two weeks ahead.Note