Grease two deep 20cm cake tins and line the base with grease proof paper .
Sift flour, salt ,cocoa ,bicarbonate of soda and the sugar into a mixing bowl .
add the vinegar to the evaporated milk .
pour in the melted butter or margarine and half of the soured milk . Beat well for two minutes .
add remaining ingredients and beat for a further two minutes .
pour into the prepared tins to bake in a moderate oven ( 180'C ) for 35 minutes .
cool slightly before removing from the tins .
when totally cooled you can place whipped cream in between the two cake layers ,and frosting on top or cream to decorate .
1 tbsp vinegar .1 cup evaporated milk .1 1/2 cup plain flour with a pinch of salt .1/2 cup cocoa .1 1/2 tsp bicarbonate of soda .1 1/4 cup Caster sugar .2/3 cup melted butter or margarine .1 tsp vanilla essence .2 eggs .