1½ cups walnut pieces, roasted and loose skins rubbed off
2 tablespoons sesame seeds, toasted
2 cups caster sugar
¼ cup cold water
3 tablespoons dark rum
100 grams each dark and white chocolate melted, optional
Put the sugar and water in a medium saucepan and slowly bring to the boil, ensuring all the sugar has dissolved before it boils. Brush the sides of the pot with a pastry brush dipped in water to wash down any sugar crystals.
Boil undisturbed until the sugar begins to change colour, then gently swirl the pan until the caramel turns a deep golden colour, about 8 minutes. Remove from the heat and add the rum, taking care as it will spit viciously.
Stir in the nuts and 1 tablespoon of the sesame seeds until well combined. Tip onto the baking tray and quickly spread out using two forks. Cool.
Break into pieces and dip half of each piece into the melted chocolate if using. Place on baking paper and sprinkle with the remaining sesame seeds while still wet. Leave to set.
Store the clusters in an airtight container between sheets of baking paper.