Preheat oven to 150°C (300°F). Place hazelnuts on a small baking tray lined with non-stick baking paper. Place the sugar and water in a saucepan over high heat and stir until sugar is dissolved. Bring to the boil and cook for 10–12 minutes or until mixture is dark golden. Pour half the caramel over hazelnuts and pour remaining caramel into 4 shallow 1 cup-capacity (250ml) ovenproof dishes. Set aside for 5 minutes or until caramel is set.
Place milk, cream and chocolate in a saucepan over medium heat. Stir until chocolate has melted and custard just comes to the boil. Remove from heat. Place eggs, extra yolks, extra sugar and vanilla in a bowl and whisk to combine. Gradually add the milk mixture, whisking to combine. Strain and pour into dishes. Place the dishes in a water bath+. Bake for 15 minutes or until set. Remove from the dish and refrigerate for 2 hours or until cold. Turn out onto plates. Break toffee into pieces and serve with the crème caramels. Serves 4.
+ Make a water bath by placing dishes in a baking dish lined with a folded tea towel and pour in enough boiling water to come halfway up the sides of the dishes. A folded tea towel in the base of the baking dish stops the dishes from sliding around and ensures the crème caramel cooks evenly as the dishes don’t touch the baking dish directly.