• 100 g (3½ oz) butter, slightly softened
• 100 g (3½ oz) caster (superfine) sugar
• 1 large egg, separated
• 1 teaspoon vanilla extract
• 100 g (3½ oz) cake flour or plain (all-purpose) flour, sifted
• 2 teaspoons finely grated lemon rind
• 1 teaspoon baking powder
• 60 ml (¼ cup) milk
• juice of half a lemon

Icing

• 1½ tablespoons lemon juice
• 50 g (1¾ oz) icing (confectioners’) sugar

Preheat your oven to 180°C (350°F/Gas 4). Butter and flour four 185 ml (¾ cup) ramekins or moulds.

Cream the butter and sugar for a few minutes, then add the egg yolk and vanilla and whisk in well. Add the sifted flour, lemon rind and baking powder and fold in with a large metal spoon to incorporate it all. Pour in the milk and lemon juice and stir well. With clean beaters, whisk the egg white in a small bowl until it is very white and fluffy, and then fold it into the cake mixture with a metal spoon.

Drop 2 heaped tablespoons of mixture into each ramekin, ensuring that the base is covered and the mixture is even. Bake for about 30 minutes, until the cakes are deep golden and a bit crusty on the top, but still soft to touch and a skewer inserted comes out clean. Put the ramekins on a wire rack to cool completely. Remove the cakes by putting a spoon or knife down the side of each ramekin and lifting them out.

To make the icing, whisk the lemon juice and icing sugar together until smooth and fairly thick, adding a little more of either if it seems necessary. Put the cooled cakes on a flat plate, make a few holes with a skewer in the top of each one and dribble the icing over the top.