1 cup milk
2 cups buttermilk
¾ cup sugar
¼ cup freshly squeezed
finely grated zest of 2 lemons
Put the milk, sugar and the lemon zest in a saucepan over a medium heat. Stir to dissolve the sugar then remove from the heat. Set aside to cool.
Add the buttermilk and lemon juice and whisk vigorously until smooth.
Pour into a freezer-proof container and freeze until partially frozen. Tip into a food processor and blend until smooth. Pour back into the container and place in the freezer.
Remove from the freezer a few minutes before serving to allow the sherbet to soften a little.