Mix together the ingredients for the light dough in a mixing bowl. In a separate bowl, mix together the ingredients for the dark dough. Once each mixture is thoroughly combined, form each into a ball and wrap separately in cling film and chill in the fridge for 1 to 3 hours.
Unwrap the dough and place one on top of the other. Between two pieces of greaseproof paper, use a rolling pin to roll the dough flat, then roll up lengthways as you would a Swiss roll. Wrap and place in the fridge for at least 1 hour.
Preheat the oven to 200 C / Gas 6. Line a tray with baking parchment.
Cut 5mm thick slices and place biscuits on the baking tray. Bake in the middle of the oven for 10 minutes, or until golden.
When your biscuits are done let them cool off before you dip half into your melted chocolate, and then into the coconut. Place on a plate lined with greaseproof paper to let them set in the fridge for about 30 minutes.