I make this cake all the time.. being we usually always have the ingredients and its soooooooo nice:

125g butter
1 teaspoon vanilla
3/4 cup castor sugar
2 eggs
2 cups self raising flour
pinch salt
1/2 cup milk

Beat butter and vanilla together until white, add sugar, beat until light and creamy. Add eggs one at a time, beating well after each addition. Fold in sifted dry ingredients alternately with the milk. When all ingredients are added, beat mixture lightly intil smooth.

Bake in well greased 20cm round or 19cm square cake tin. Back in moderate (180) oven 55 to 60 minutes. (do keep an eye on it though.. i usually check it at about 35 minuites)

And thats it. Topped with a good butter icing (50g butter, 125g icing sugar, 1 teaspoon milk & 1/2 teaspoon vanilla).. and its sooooo nice.. in fact im eating a slice right now!