For the madeleines, put the sultanas into a saucepan, cover with water and bring to the boil. Remove from the heat and leave to soak overnight to plump up. Drain and set aside.
To make the lemon curd, put the egg, yolk, sugar, and lemon zest and juice in a bain marie (the top of a double saucepan or in a heatproof bowl set over a pan of simmering water). Stir until the sugar dissolves t