Preheat oven at 160 deg C. Line a 20cm cake pan with baking paper.

Sift flour, cocoa powder and baking soda ogether in a bowl. Add in sugar and mix well.

Warm butter at low heat till melted and stir in instant coffee powder.

Lightly whisk eggs, butermilk and vanilla extract together in a cup. Then pour into the flours together with melted butter. Gently fold well with a rubber spatula followed by the chocolate chips and chopped walnuts.

Pour chocolate mixture into prepared pan and bake for about 25-30 mins until cooked when tested with a skewer.

Cool in pan on a wire rack about 10 minutes, before lifting out onto rack to cool.

Cut brownies into 16 pieces and dust with some cocoa powder and icing sugar over it. Serve immediately or store in an airtight container.