Banana Bundt Cake with Coconut Cream Cheese Frosting

Preheat oven to 180 degrees C (350 degrees F). Using a kitchen brush grease very well a large bundt pan (for best results I pour into the pan ½ tbs all purpose flour and 1-2 tbs oil and use the brush to mix them and spread the mixture all around).
In a bowl combine the two kinds of flour, cornstarch and baking powder.
Mash the bananas or puree them in a food processor.
Beat the eggs and sugar with a mixer, then gradually add the oil, yogurt and vanilla and the mashed bananas.
Use a rubber spatula to fold the dry mixture into the batter into batches.
Pour small quantity of the batter in a cup and add in the cocoa powder. Mix well until the cocoa is completely absorbed. This part will be used to make the marble effect of the cake.
Pour half of the uncoloured batter into the prepared pan. Spoon the cocoa batter on top. Cover with the remaining batter. If you want to make the cake even more marble-like, you can go with 3 layers of uncoloured batter with 2 layers of cocoa batter in between them.
Bake for 50-60 minutes or until a wooden skewer inserted in the centre comes out almost clean.
Let the cake cool until room temperature before frosting it.