Grease and flour the cake tin to prevent sticking. Preheat the oven to 170 degrees C.
In the stand mixer, beat the softened butter until fluffy.
Add the sugar bit by bit and continue to beat until soft.
Add the eggs, one at a time, mixing well after each one.
Add the vanilla bean paste and mix well.
Measure the dry ingredients (flour, bicarb, pinch of salt) in another bowl. Add half into the mixer bowl. Then add half the yoghurt.
Repeat and add the remaining flour mixture and yoghurt. Mix gently to ensure it is well blended.
Take about a third of the cake batter and place in another bowl, then add a small amount of purple gel colour, to your desired shade, and mix well.
Spoon the plain and purple cake batter alternately into the tin until all used up. Take a knife or skewer and marble the colours together.
Bake for 60 minutes or until golden and a skewer comes out clean.
Allow to cool for 5-10 minutes them remove from the bundt tin and leave to cool fully.
In a couple of small bowls make the icing: mix approx 1 tsp of water with enough icing sugar to make a paste. Make sure it is not too runny. Colour as desired using the gel food colours. Drizzle over the cooled cake then decorate with Mini Eggs.