Unicorn Head Cake

Name: Unicorn Head Cake
Prep time: 1 h
Cook time: 3 h
Total time: 3 h
Yield: 20 slices
Ingredients: 375 g unsalted butter; 375 g caster sugar; 6 large eggs; 375 g self-raising flour; 60 g milk; 1 tsp baking powder; 2 tsp natural vanilla extract; yellow food colouring gel; 450 g unsalted butter; 900 g icing sugar; 1 tsp natural vanilla extract; 45 g milk; yellow food colouring gel; 600 g fondant icing; 200 g fondant icing; edible gold glitter spray; water; coloured sugar sprinkles