Preheat oven to 180 degree C. Line a 20 cm square cake pan with foil and grease with butter. set aside.

Take flour, cocoa, baking powder in a bowl and whisk well.

Take butter and chocolate chips in a sauce pan and melt over low heat till completely molten.

Now set aside to cool a bit.

Add in sugar and mix well. Add one egg at a time and whisk well.

Add in vanilla and mix well.

Add in the flour mix and fold gently.

Add in walnuts and fold gently.

Spoon this into the baking pan and bake for 40 to 45 mins.

Remove it from oven and cool for 30 mins.

Now remove from pan and cool completely.

Cut and serve.