In a small pot melt butter with sugar on small/medium heat. Add milk and take off the heat.
Add coconut and mix very well making sure all the coconut bits are covered. Set aside to cool down.
In a big bowl beat the egg whites with a pinch of salt. Add potato starch by the end.
Add coconut mixture to the egg whites and combine using a spatula. Set aside for a minute to cool down.
Preheat the oven to 180C and prepare your baking tray by covering it with parchment paper.
To form the cookies it is best to do it with lightly wet hands. Form small to medium balls and place them on the baking tray living some space in between. Flatten each cookie a bit with your fingers. You should end up with around 28 cookies.
Bake for 10 to 14 min. Let them cool down before enjoying with a cup of tea or coffee.