From Diana Henry's Crazy Water, Pickled Lemons: Enchanting Dishes from the Middle East, Mediterranean and North Africa. This recipe uses an ice cream maker, freezing time not included. Use the general guide lines on your specific ice cream maker.
Heat the milk just to the boiling point, then add the basil leaves and lemon rind. Take off the heat and leave to infuse for 1 hour.
Beat the sugar and yolks together until pale and fluffy. Strain the milk, pressing the basil and lemon rind to extract any last bits of flavour. Stir this into the egg and sugar mixture.
Put your bowl on top of a sauce pan of simmering water. Stir the liquid in the bowl constantly until it thickens slightly. If you scrape the back of a spoon through the mixture and it leaves a path, your custard is ready. Immediately pour it into another bowl and leave to cool.
When cool, add the lemon juice to the custard. In a separate bowl, beat the cream lightly. When the cream has thickened, add to the custard mixture.
Freeze in an ice cream maker, stopping three times during the freezing process to beat the mixture with an electric beater.