Pre heat oven to 180c°. Line 4cm deep 20×20cm backing tray

Using a electric mixer mix butter and sugar until pale and creamy. Add eggs one at a time until well combined.

Stir in flour, cocoa and baking powder. Mix until well combined pour into prepared tray and sprinkle with chocolate.

Bake for 20-30 minutes until just cooked. Allow to cool before removing from tray.