Before decorating, ensure that your cupcakes are completely cool – otherwise you’ll have a sticky, melted mess.
In a stand mixer, start mixing your butter and sugar on medium speed. Add milk one tablespoon at a time and increase the speed.
Your buttercream should form stiff peaks – so add confectioners’ sugar and milk accordingly. Milk will loosen it up, sugar will make it more stiff.
Divide the buttercream in two bowls. Colour one violet (about 1 small drop) and the other, pink (2 red drops of the red). Mix each bowl until the buttercream is completely coloured.
Add both coloured buttercreams in a large bowl and fold into one another, ensuring that the colours blend but don’t mix. Using a piping bag, frost each cupcake (I used a 1M Wilton tip).
Roll fondant into spheres, about 1/2 an inch in diameter. Then roll them out so that they’re about 3 inches long
Lightly “bend” your fondant strip (halfway, so that the ends are even) and start twisting to create the shape of the unicorn horn. Place on a baking sheet and brush lightly with your cake dust.
Allow the unicorn horns to dry for about 20 minutes and place on your frosted cupcake. Add a candy flower to each one.