You will need

• 250g mascarpone
• 100g caster sugar
• 3 eggs, separated
• 2 very ripe (black speckled)
• bananas

• 50g butter
• 100g demerara sugar
• 50ml brandy
• 100g California raisins
• 50g walnuts, coarsely chopped

Method

• Beat the mascarpone, sugar and egg yolks together until light and fluffy.
• Whiz the bananas until smooth using a liquidiser or hand blender and stir them into the mascarpone mixture.
• Whisk the egg whites until they form stiff peaks and then fold gently into the mascarpone mixture. Transfer into a freezerproof bowl and freeze for several hours, or overnight.
• To make the sauce, put the butter, sugar and brandy together in a saucepan and heat gently until the butter has melted and the sugar has dissolved. Turn the heat up a notch and bubble for 3-4 minutes, until thickened. Stir in the walnuts and raisins.
• Leave to cool (but do not refrigerate).
• To serve, scoop the semifreddo into pretty glasses and then pour over the sauce.