Preheat oven to 180 degrees. Line an 8 inch brownie pan with parchment paper and set aside.

Combine flour, soda, cocoa powder, sugar and salt and whisk well. Set aside.

Pour the water on the chocolate and whisk till melted. Add the margarine and beat well till combined. Add in the vanilla extract.

Pour the wet ingredients over the dry ingredients and fold in using cut and fold method, with a spatula till well moistened. Fold in the walnuts.

Pour the batter into the prepared pan and bake for 25 minutes.

Take out and cool completely in pan, before cutting and serving!