vanilla choc marble moist steam cake

Ingredient	method
Choc cake ingredient:  90g butter 40g caster sugar 90g condensed milk  1 A egg 25g cocoa powder 50g superfine flour 1 tsp vanila est. 0.5 tsp baking powder 0.5 tsp baking soda  Vanilla cake ingredient:  90g butter 20g caster sugar 90g condensed milk  1 A egg 2 tsp vanilla extract 80g superfine flour 0.5 tsp baking powder 0.5 tsp baking soda	1. Beat egg in a bowl, add other ingredients (except dry ingredients) and mix well. 2. Sift dry ingredients and mix into the batter, stir well. Repeat step 1 and 2 for the vanilla cake. 3. Spoon the choc batter into cupcakes case and then spoon the vanilla batter to create marble pattern. 4. Put the case into the steamer for 20 minutes.