Melt the butter and chocolate till smooth by double boiler or directly on stove (ensure not to burn!) and allow to cool.
Beat eggs and sugar till it is mixed well.
Add the melted mixture, cocoa powder and baking powder and beat again to combine well.
Finally add the flour and mix well with a spatula till no lumps are there. The batter will be quite thick.
Grease a microwavable pan with butter. Pour the batter into the pan.
Sprinkle all the nuts on top of the batter and spread well.
Microwave on high for a maximum of 5 minutest till done. Mine was done in 4.5 minutes.
Allow to cool, slice and devour!!! :)