1 1/4 cups mixed berries (such as blackberries, raspberries, blueberries, strawberries and red currants)
2 oz white chocolate, chopped into small pieces
1/4 cup heavy cream
To freeze the berries, line a rimmed baking sheet with baking parchment or waxed paper and arrange the berries in a single layer. When they are frozen, transfer to small freezer bags. They will last for 1 month and are also good in smoothies.
Take the berries out of the freezer and divide between two bowls. Allow them to defrost slightly at room temperature, for about 10 minutes.
Put the chocolate and cream in a microwaveable bowl and cook for 10 seconds, stir, and repeat heating and stirring until chocolate has just melted (it will take 4 to 5 blasts) and you have a smooth sauce.
Alternatively put the cream and chocolate in a small heatproof bowl over a pan of simmering water and stir continuously until the chocolate has just melted.
Pour the hot sauce immediately over the berries and serve at once.