Sunny Family Chocolate Cake

Batter
1/3 cup cocoa
1/2 cup self-raising flour
2/3 cup plain flour
1/2 tspn bicarb soda
125g butter, softened
1 1/4 cups castor sugar
3 eggs
1 tspn vanilla essence
1/2 cup milk

Icing
2 cups icing mixture
3/4 cup cocoa
50g butter, softened
1 tspn vanilla essence
50-100ml boiling water

1. To make batter sift dry ingredients into a bowl.  Add all remaining ingredients.
2. Mix with electric beaters on low speed until combined.  Increase speed to high and beat for 1-2 minutes.
3. Spread mixture into a greased and lined 20cm round cake pan.  Cook in a pre-heated 160'C oven for 60-70 minutes, or until skewer inserted into centre comes out cleanly.
4. Leave in pan to cool for 10 minutes before turning onto cooling rack. 
5. To make icing sift dry ingredients into bowl.  Add butter and vanilla, then slowly drizzle in boiling water, mixing well after each addition, until icing is smooth consistency.  Icing can be make as runny as you like by adding more boiling water.
6. When cake is cool, cover with icing.