3 Clarence Court duck eggs and the equivalent in weight of:
2 tbs milk
2 tsp vanilla extract
good quality jam
Pre-heat the oven to 170C.
Line 2 x 20cm cake tins with baking parchment.
In a bowl, cream the butter and sugar together and then gradually beat in the eggs one at a time.
Add the milk, vanilla and flour and stir until just mixed.
Divide equally between the two tins and bake in the oven for 25 mins or until cooked.
Turn out onto a cooling rack and peel off the paper.
When cool, place onto a serving plate and spread the underside with jam, and put the two halves together, bottom to bottom.
Dust with icing sugar and enjoy!