Baked in an 7.5 inch square pan
Scoop cocoa/coffee mixture into the ⅓ filled bowl and mix thoroughly.
Line an 7.5 inch square pan with baking paper and pour ½ of the plain batter.
Spoon about ½ cocoa/coffee mixture and pour over the plain batter in random circular streaks.
Pour in the remaining plain batter and spoon in the cocoa/coffee mixture.