In a bowl with a mixer cream the margarine and sugar till light and fluffy.

Sieve the flour and baking powder together and set aside.

Preheat the oven to 160 degrees. Grease your baking tin and set aside.

Beat in one egg at a time,then add vanilla extract. Until well mix and don't over beat.

Set aside the mixer and fold the flour in portions.

Add the buttermilk and continue folding till smooth.

Divide the mixture into two portions. Add unsweetened Cocoa in one portion and mix well not using a mixer but by folding.

In the greased tin pour bit of the Cocoa mixture then the plain mixture. Keep alternating til both mixtures are in the greased tin.

Using a skewer or toothpick make lines from the middle of the tin to the edges.

Bake for roughly an hour. Check by dipping a skewer to check if ready, the skewer will come out clean.

It's ready.