Mash the coriander root, shallot, galanga, kaffir lime leaves and lemongrass in a mortar, put them in the pan and cook for 1-2 minutes. Add the chicken pieces and cook for 3-4 minutes or until done. Stir in the young coconut, fish sauce, sugar, coconut milk and lime juice, and let the soup boil for another 2 minutes. Add the peppers and coriander, scoop the soup into whole, young coconuts, garnish with dried peppers and put them on the table.