Put the cream and sugar in a small saucepan. Heat gently, stirring, till it just reaches a boil. Let it bubble for exactly 2 minutes — no more, or it’ll scorch and start tasting like regret.
Juice the lemon and zest half of it.
Take it off the heat, stir in the juice and zest, and watch it thicken almost instantly.
Pour into four small glasses or ramekins.
Cool to room temperature, then chill at least 4 hours.
It’ll set like satin, somewhere between mousse and custard.
Notes
Serve it with shortbread, crushed biscuits or a handful of redcurrants