Make the royal icing according the instructions below. Divide into 4 batches, leaving one white and colouring the other three respectively in black, orange and violet. Cover with a damp tea towel to prevent crusting.
Royal Icing Recipe
3 table spoons Wilton Meringue Powder
450g icing Sugar
6-7 tablespoons Water
Beat all ingredients in large bowl with electric mixer until icing forms peaks and loses its sheen: 7-10 mins for a stand mixer, 10-12 mins for a hand mixer.