Beat margarine in a bowl for 1-2 minutes until light. You can use a whisk or a cake mixer. Add sugar and beat.
Crack in the eggs and whisk together until combined.
Add the flour, baking powder and salt and using a spoon mix the mixture until well combined and there are no lumps.
Pour in vanilla essence and milk and mix again. If the mixture is too thick, feel free to add some more milk.
Remove 3 scoops of the vanilla cake batter and place aside.
Mix the cocoa powder into the remaining batter.
Into a greased pan, add the vanilla and chocolate batter one scoop at a time alternating between the two. So, first goes the chocolate batter, on to it goes the vanilla, then chocolate, vanilla etc.
Light up a jiko and place a sufuria on top of it. In the sufuria, place 3 stones. Try look for 3 stones that have a sort of flat surface so the cake pan stays upright. Cover with a lid and let preheat for 5-10 minutes.
Once preheated, place the cake pan on the stones and cover with the lid. Place some pieces of burning charcoal on top of the lid.
Let the cake bake for 50 minutes to an hour. Make sure the heat is medium. Too hot will burn the bottom of the cake without cooking it and too cold won’t cook the cake. Once the cake is on, make sure to add some more coal halfway so that it does not cool down. This will ensure that the cake doesn’t fall back after rising. The time for the cake to cook will depend on the heat, so if it is not ready after 50 minutes, let cook for another 10-20 minutes.
The cake is ready when a skewer inserted into it comes out clean. Let cook in the pan for 10 minutes and then remove. Slice up and eat warm with a cup of chai or let cool down completely and ice it with some buttercream or whipped cream.