1/2 can (400 grams for full can) condensed milk 
140 grams (5 oz.) self-raising flour 
1 level teaspoon baking powder 
1/2 teaspoon soda bi-carb 
60 ml. (2 fl.oz.) melted butter or margarine 
1 teaspoon vanilla essence

Sieve the flour, baking powder and soda bi-carb together. 

Mix the flour mixture, condensed milk, melted butter, essence and
75 ml., water and beat well. 

Pour the mixture into a greased and dusted tin. 

Bake in a hot oven at 200 degree C (400 degree F). Then reduce
the temperature to 150 degree C (300 degree F) and bake for a
further 10 minutes. 

The cake is ready when it leaves the sides of the tin and is
springy to touch. When ready, take out from the oven and leave
for 5 minute. Invert the tin over a rack and tap sharply to
remove. Cool the cake.