Heat the oven to 350°F (180°C) or gas no. 4. Generously grease 9 fluted cake moulds set on a baking tray or a tray of bun tins. Sift the flour and salt on to a plate and set aside. Arrange currants in the base of prepared tins.
Cream the butter and sugar in a mixing bowl until soft and light. Mix the egg and finely grated lemon rind