Preheat the oven to 180C / 356F .Prepare two large baking trays with greaseproof paper and spread the coconut evenly across the trays. Place in the oven for 5 minutes to lightly toast the coconut, removing when just starting to brown.
Meanwhile, combine the egg whites, xylitol, vanilla and salt in a large bowl. Whisk for 1 - 2 minutes until lightly fluffy and frothy.
Remove the coconut from the oven and let it cool slightly. Combine with the egg whites and fold through until all coconut is uniformly moistened. If the mixture appears a little too sticky to form a ball at this stage, add coconut flour 1/2 tablespoon at a time. Be aware the coconut flour is very absorbent so add with caution.
With wet hands, roll the cookie dough into tablespoon sized balls. These don't spread so you can fit 12 on a tray easily.
Return the cookies to the oven and cook for 12 - 15 minutes until golden to your liking - I like them on the crispier side so usually get closer to 15 minutes.