1.Preheat oven to 180°C/350°F. Grease a 20cm x 30cm (8in x 12in) rectangular slice pan; line base and long sides with baking paper, extending the paper 5cm (2in) over the sides.
2.Combine sifted flours and cocoa, coconut, sugar and melted butter in a medium bowl; press mixture evenly over base of pan. Bake for 20 minutes or until firm to the touch; cool for 15 minutes.
3.Meanwhile, make coconut rough filling. Combine ingredients in a medium bowl.
4.Place chocolate in a medium heatproof bowl over a medium saucepan of simmering water (make sure the base of the bowl doesn’t touch the water); stir until smooth.
5.Spread coconut rough filling evenly over warm base; top with melted chocolate. Refrigerate for 2 hours or until firm.
Slice can be stored in an airtight container in the fridge for up to 1 week.