First step is to make the brown butter. Melt the butter in a saucepan on a low flame till the butter becomes brownish and gives a slighly burned taste. Allow it to cool completely.
Preheat oven to 180 degrees. Line an 8 inch square pan with parchment paper and grease well.
In a bowl, whisk together the melted brown butter, brown sugar, egg and vanilla till nicely whipped.
Sift in the flour, salt, baking powder and baking soda. Add the chips and nuts and fold in the batter completely. It will be thick.
Spread onto the prepared pan and bake for 25 minutes or till the top looks set.
Allow to cool completely before slicing and serving.