Preheat oven to 180C and grease and dust baking tin, keep ready.

In a large bowl, beat the yoghurt till smooth. add sugar and mix till it dissolves. Add baking powder and soda and mix well till its frothy.

Add oil and vanilla mix well. The start adding in the flour and fold in gently till its incorporated.

Remove about 3-4 tbsp and put in a bowl, add in the cocoa powder and mix well.

Pour half of the vanilla batter in your tin and drop half of the chocolate batter on top of the vanilla. Use a knife or a skewer to swirl it. Add the rest of the vanilla batter and the remaining chocolate batter and swirl gently only on top dont go too deep.

Bake in the oven for 35- 40 mins until it looks form and a toothpick comes out clean. Let it cool completely.