Whisk together the milk, sugar, crème
fraîche, lemon zest and vanilla. Set
aside for 10 mins for the sugar to melt.
Churn in an ice-cream machine, following
manufacturer’s instructions, before
freezing. Or freeze for 1 hr, then give
a good whisk and return to the freezer
for another hour. Repeat 3 or 4 times
until it becomes solid.