Select 12 pansies of different colours. and remove the stalks. Keep about 8 whole and separate the petals from the remainder.
Whisk an egg white to a light froth and, using a small clean paintbrush, paint each petal with a little of the egg. Toss each gently in a small bowl of caster sugar and shake off any excess. Lay the petals out on a baking tray lined with baking parchment.
Leave to dry for at least 2 hours, preferably overnight. Place the whole flowers in the centre of the cake and scatter the petals around.