Raspberry cheesecake ice cream

Method

1. Put the raspberries in a bowl with 1 tbsp sugar and lightly mash. Set aside to macerate while you make the custard./li>
2. Put the milk, mascarpone and a pinch of fine sea salt in a medium saucepan. Heat gently, stirring often. Once the mixture is steaming hot, remove the pan from the heat. In a separate bowl, use a balloon whisk to mix the egg yolks and 100g sugar for 1 minute until thoroughly combined.
3. Half-fill the sink with cold water. Gradually whisk the hot cream into the yolk mixture, whisking continuously to form a custard. Return the custard to the pan and cook over a low heat, stirring all the time, until it reaches 82°C on a sugar thermometer (or becomes thick enough to coat the back of a spoon). Don’t let the custard boil or it will scramble. As soon as it reaches the right temperature or thickens enough, plunge the base of the pan into the sink of water to cool. Speed up the cooling process by stirring the mixture every so often.
4. Purée the macerated raspberries in a food processor or blender until smooth, then push through a sieve to remove the seeds. You should be left with around 170g raspberry purée.
5. Once the custard is at room temperature, divide the mixture between two containers. With a large metal spoon, fold the raspberry mixture through one batch of custard until uniformly pink. Cover the surface of both containers with baking paper and chill for at least 4 hours or overnight.
6. The next day, pour the pink custard into an ice cream machine and churn for 25-45 minutes (depending on your machine) until it reaches the texture of thick whipped cream. Transfer it into a container large enough to fit both halves of the churned custard and keep in the fridge while you churn the second batch in the same way. Once both batches of ice cream are churned, swirl the second batch into the first, being careful not to over mix as it will lose its ripple, and adding the crumbled biscotti as you do so. Cover and freeze for at least 4 hours until ready to serve. It will keep for up to 3 months in the freezer. Soften out of the freezer for 5-10 minutes before serving (see serving tip).