Preheat the oven to 180 C, spray a 8"x8" pan with cooking spray and line with baking parchment.
In a large bowl, whisk together the oil, buttermilk and vanilla extract.
In another bowl, sift together the flour, cocoa, coffee powder, soda bicarb and sugar.
Pour the wet mixture into the flour mixture and combine gently till just blended. Do not overmix, else the soda bicarb will go flat.
Pour the batter into the prepared pan and bake for 15-20 minutes till done (brownies must remain slightly underdone to get that fudgy texture).