Instructions

Combine the milk and heavy cream in a heavy-bottomed pan, place over a medium-high heat and bring to the boil.
Meanwhile, whisk the sugar with the egg yolks until pale and fluffy. Remove the hot cream mixture from the heat and whisk a small amount into the eggs (not too much - you want to avoid making scrambled eggs), then start pouring the custard mix back into the hot cream, continually whisking to incorporate

Return to the heat and continue to stir, bringing the mixture to 80˚C. Remove from the heat, whisk in the buttermilk, pass through a fine sieve, chill and churn in an ice cream maker