Mix together the yogurt and 2 tbsp honey and transfer to a freezer-proof container, place in the freezer for 2 hours.
Meanwhile, mix together the walnuts, remaining honey and oil and spread out onto a parchment lined baking tray, bake for 7-8 minutes until golden, allow to cool completely. Reserve some clusters for garnish.
Place the raspberries in a small saucepan with 1 tbsp water and cook gently for 4-5 minutes until a pulp is formed, allow to cool completely, then press through a sieve and discard the pulp.
Stir the yogurt and freeze for a further 2 hours. Stir again with a fork to mash down any large ice crystals and stir in the chopped caramelised walnuts. Gently stir in ¾ of the raspberry sauce to create a marbled effect and freeze again for 2 hours or until needed.
Remove from the freezer 20-30 minutes before required. Serve sprinkled with reserved walnut clusters.
