In a large bowl, cream together the butter and sugar until smooth. Beat in the eggs one at a time then stir in the vanilla and sour cream. Combine the flour and bicarb soda; stir into the creamed mixture until well blended. Use a wooden spoon to stir in the coconut and macadamia nuts. Drop dough by rounded teaspoons 5cm apart onto ungreased baking trays.
Bake for 10 to 12 minutes in the preheated oven until edges are golden brown. remove biscuits from baking trays to cool on wire racks.