Place 2 cakes on a work surface. Use a large serrated knife to trim 1 long side of each cake. Place cut sides together. Place template on top of cakes. Use a small sharp knife to cut out butterfly. Place a little icing on bases of cakes to secure to a cake board or serving platter.
Place two-thirds of remaining icing in a bowl. Add a few drops of red and blue food colouring. Stir until well combined and purple. Spread icing over the side and top of the cake to cover.
Place remaining icing in 2 separate bowls. Add a few drops of yellow food colouring to one bowl and stir until well combined. Add a few drops of green food colouring to the second bowl and stir until well combined.
Spread green icing on the top 2 wings in a teardrop shape. Place the green jelly beans around teardrop to make a border. Arrange the pink jelly beans inside the border. Repeat with yellow icing, yellow jelly beans and orange jelly beans on the bottom 2 wings. Place 3 crawlers between wings on both sides of the cake.
Separate the fizzers into colours and place in separate bowls. Place 2 white fizzers at the top to make eyes. Place coloured fizzers in rows, alternating the colours for each row, down the centre, overlapping slightly. Place 2 crawlers at the top of the head to make antennae.
