This works as a gorgeous topping for all sorts of desserts, and also as a component in Jamie's Taco Party from Together – see the full collection of menus here.
GET AHEAD Put the caster sugar into a pan with 50ml of water and place on a medium-high heat for about 6 minutes, or until you’ve got a chestnut brown caramel – please don’t be tempted to stir, taste or touch the mixture, just give the pan a gentle swirl occasionally. Gently stir in the hazelnuts, then pour the mixture on to an oiled baking sheet. Leave to cool, then use a pestle or the end of a rolling pin to smash up the brittle until you’ve got a mixture of fine and chunky. Cover and store until needed. Delicious served with Chocolate semifreddo.