Pudding: Cream the butter and sugar until light and fluffy. Stir in the flour and baking powder.
Add the eggs and combine well then stir in the cocoa slurry. Finally add the broken chocolate pieces.
Bake in a preheated oven at 180 degrees C for 18 to 20 minutes.
Sauce: In a bowl over a simmering saucepan of water add all the ingredients until the butter and chocolate have melted and everything is well combined.
To Serve: Cut a piece of the still warm pudding then serve in a bowl covered with the chocolate sauce.