Step 1: 1. Set the oven to 180C/gas 4. Lightly butter two sandwich tins, each with a diameter of 20cm.
Step 3: 2. Cream together the butter and sugar together until light and fluffy, and then slowly add the beaten egg.
Step 5: 3. Fold in the sifted flour and spoon the mixture into the prepared cake tins.
Step 7: 4. Bake for 20 minutes. Leave to cool and then remove from the tins.
Step 9: 5. Whip the cream until thick and use it to fill the sponge with the jam.
Step 11: 6. Dust liberally with icing sugar to serve.