For the coconut biscuits, preheat the oven to 150 degrees. Boil the sugar, milk and 350 g of coconut flakes, stirring constantly, until the coconut flakes are soft.
Let the mixture cool down a bit. Add the egg whites and heat again. Remove the saucepan from the heat. Fold in the remaining coconut flakes.
Spread the mixture evenly on a baking sheet with a teaspoon and bake until golden brown.
Let the coconut biscuits cool on a cooling rack so that they do not become too dry.