Preheat oven to 180C / 350F and prepare baking pan.
Sift the flour and cocoa together and set aside.
Mix the butter/margarine and sugar together and add in vanilla.
Separate the eggs and add the yolks to the butter mixture. Mix well.
Slowly alternate adding the flour and cocoa mixture and milk into the butter mixture and mix well.
Beat egg whites until stiff and gently fold into mixture.
Pour into prepared pan and bake at 180C for 30-40 minutes.
Recipe Notes
To make this gluten free: Substitute the 2 cups self-raising flour for 1 1/2 cups rice flour, 1/3 cup potato starch, 1/3 cup tapioca starch, 1 tsp xanthan gum and 4 tsp baking powder.