Chewy peanut butter and plum ice cream sandwiches

Method

1. Make the ice cream at least 1 day before you want to serve it. Put the plums in a food processor or blender with 25g of the caster sugar and 60ml of the milk, then whizz to a smooth purée. Set aside.
2. Pour the cream and remaining 100ml milk in a saucepan and set over a low heat. In a large bowl, whisk the egg yolks and remaining 150g sugar until smooth. As soon as the cream mixture is hot but not boiling, pour slowly into the eggs, whisking continuously.
3. Return the mixture to the pan, then cook over a low heat, stirring. You’re looking for a light custard that coats the back of a spoon. Once it’s ready, plunge the base of the pan into a sink or bowlful of cold water, then leave to cool completely.
4. Whisk the puréed plums into the custard. Chill for at least 6 hours.
5. Churn the plum custard in an ice cream machine according to the manufacturer’s instructions. If you don’t have a machine, put the mixture in an airtight freezerproof container and freeze, whisking with an electric mixer every few hours to break down any ice crystals, until frozen and smooth. Keep frozen until needed (see Make Ahead).
6. To make the cookies, heat the oven to 180°C/160°C fan/gas 4. In a large mixing bowl, beat together the butter and peanut butter until smooth. Mix in both the sugars and the vanilla. Beat in the egg, then fold in the flour, baking powder, cinnamon and a pinch of salt.
7. Divide the dough into 16 even balls and press them onto the lined sheets, spaced apart to allow room for them to spread. Bake for 10 minutes until lightly golden. Leave to cool on a cooling rack.
8. To assemble, put a scoop of ice cream in the centre of each cookie, then put another cookie on top. Roll the edge of the ice cream sandwich in the chopped peanuts, if using.