Divide other half into three small bowls. Add yellow food colour to one small bowl until desired shade is achieved and mix well. Add equal amounts of yellow and blue food colour to the second small bowl to make a green icing. Add equal amounts of blue and red food colour to the third small bowl to make a purple icing. Place coloured icings in small resealable plastic bags. Seal. Cut tiny tip off corner of each bag. Frost each cookie with white icing using spatula or knife. Pipe coloured icings decoratively over each "King cake." Makes: 3 "King cake" cookies ----