2 cups sugar
300ml pure cream
2 tbsp liquid glucose
200g dark cooking chocolate, chopped
140g hazelnuts, roasted and peeled (see tips, below)
Put sugar, cream, glucose, chocolate and butter in a medium saucepan over a medium-low heat and stir until melted. Bring to a simmer. Without stirring, simmer for 15-20 minutes or until syrup reaches 115°C (soft ball stage) on a sugar thermometer (see tips, below). Remove from heat. Allow to cool for 40 minutes.
Grease, then line a 20cm square cake tin with baking paper. Put mixture in the small bowl of an electric mixer and beat for 5 minutes or until thick. Stir in nuts, then spread into prepared tin. Refrigerate overnight, then cut into squares to serve.
If you buy unroasted hazelnuts, spread nuts on a baking tray and roast in a preheated 180°C oven for 10 minutes. Tip hazelnuts onto a clean tea towel.
To test if syrup is at soft ball stage without a sugar thermometer, drop a teaspoon of syrup into cold water. Gather it up with your fingers: if it forms a soft and pliable ball, it is ready.