Recipe from The Australian Women's Weekly
125 g butter
1/3 cup caster sugar
3/4 cup self-raising flour
1/4 cup custard powder
1 tablespoon custard powder
1 tablespoon caster sugar
2/3 cup milk
1 rounded teaspoon butter
2 teaspoons vanilla essence
Grease and line a deep 9 cm round cake pan. Preheat oven to 175 C.
Make the custard first so it has time to cool. Blend the custard powder and sugar with the milk in a saucepan. Stir constantly over heat until the mixture boils and thickens, then stir in the butter and vanilla. Let it cool down to room temperature.
To make the cake, cream the butter and sugar until light and fluffy, then add the egg and beat until combined. Sift the flour and custard powder and stir into the creamed mixture. Spread half of the cake batter into the prepared pan, then pour in the custard, pushing it out towards the sides, leaving about 2 centimetres or so at the edge. Spread the remaining cake batter over the top.
Bake in the oven for about 35-40 minutes.