Lemon Custards with Raspberry Sauce

• 1 large lemon with thin, unblemished skin
• 6 oz / 170 g caster sugar

Finely grate the zest from the lemon into a bowl. Squeeze a drop of lemon juice over it, and mix in half the sugar. Let it steep for 20–30 minutes, then beat in the eggs and egg yolks. Bring the milk to scalding point, and pour it over the eggs, stirring continuously. Strain the custard through a not-too-fine sieve (you want the lemon zest to come through but not the white threads from the eggs