Pain au mint chocolat ice cream sandwich

Method

1. Put the milk, cream and a pinch of fine sea salt in a medium pan, heat gently until steaming hot, then remove the pan from the heat. In a separate bowl, use a balloon whisk to whisk the egg yolks and sugar for 1 minute until thoroughly combined.
2. 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 probe or 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.
3. Once the custard is at room temperature, whisk in the peppermint extract and green food colouring – go slowly and stop when you’re happy with how green it is. Pour the mixture into a container, cover the surface with baking paper and add the lid, then chill overnight.
4. The next day, slice the croissants lengthways into 1cm slices, toast them on both sides under a hot grill, then whizz in a food processor into a fine crumb. Melt the chocolate in 10 second blasts in the microwave or in a heatproof bowl set over a saucepan of gently simmering water (don’t let the bowl touch the water) until liquid.
5. Pour the chilled 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. When it’s almost churned, with the motor still running, add the croissant crumbs, then slowly pour in the chocolate in a thin stream (the chocolate will solidify as it hits the ice cream and break into chips). Transfer to a lidded container, seal and freeze for at least 4 hours until ready to serve. It will keep for up to 3 months in the freezer. Soften for 5-10 minutes out of the freezer before serving (see serving tip).