Preparation:

• Put the cream and milk in a saucepan over medium heat, bring just to the boil then take off the heat and leave to cool.
• Half-fill a separate saucepan with water and bring to a simmer.
• Prepare a cold-water bath: put cold water and a few ice cubes in a large bowl.
• Whisk the sugar and egg yolks in a heatproof bowl to combine, add the cooled whipped cream and milk mixture and mix well.
• Place the bowl and its contents on top of the saucepan of simmering water. The bottom of the bowl must not touch the water. Use a whisk to stir the mixture constantly for about 10 minutes until thickened and smooth.
• Place the base of the bowl with the finished ice cream mixture in the cold-water bath to cool. Stir for about 8 minutes and then chill in the refrigerator for at least 30 minutes. The mixture is now ready to use or freeze as desired.