Zebra cake - Carnavil

!Prepare the food colourings the day before (they can be kept in the refrigerator for 6 days in airtight bottles).
Yellow food colouring!

1. In a saucepan, bring the water and turmeric to the boil and let boil for 2 minutes. Turn off the heat, set aside and strain through a Chinese strainer. Store in the refrigerator.  
Green food colouring
2. In a saucepan, bring the water and spinach to the boil and let boil for 2 minutes. Remove from the heat, purée, then strain through a Chinese strainer.  Store in the refrigerator.  
Purple food colouring
3. In a saucepan, bring the water and blueberries to the boil and let boil for 2 minutes. Remove from the heat, purée, then strain through a Chinese strainer.  Store in the refrigerator.  

Cake Preparation
4. Add the yogurt followed by the oil, the two types of sugar, the flour, baking powder, ground almonds and beaten eggs to hemispherical bowl. Combine well.
5. Divide the batter into 3 equal parts. Add a few drops of each colouring to each and stir until the desired colour is obtained. Make the batters a little darker than you want for the end result as the colour fades a little while the cake is baking.
6. Butter the cake mould. Pour in a layer of the purple batter, followed by the green batter and finally the yellow batter. 
7. Bake in a 180°C oven for 25-30 minutes.

Icing
8. Beat the softened butter for a few minutes, then add the icing sugar and combine until smooth and soft.
9. Ice the cake and top with the sugar decorations.