Sift the flour and baking powder in a mixing bowl. Add 1/2 cup desiccated coconut and mix well. Set aside.
Place butter in the bowl of your stand mixer (you can use your hand mixer or a whisk too), sift in powdered sugar, beat on low speed initially, until the powdered sugar is mixed with the butter, then increase the speed to medium and beat until light and creamy.
Add vanilla extract and continue to beat.
Now switch to the lowest speed and add the flour and coconut mixture in 3 parts incorporating the butter into the flour. Gently bring the dough together. Do not knead.
Add milk and mix for another few seconds until you have a soft dough. Test it by pinching a tablespoon of dough, it should form a smooth ball. Add another teaspoon of milk, only if required to adjust the consistency of the dough. Do not add too much, or else the dough will turn sticky.
Use a tablespoon to measure the dough, roll each dough ball between your palms then flatten it and dust in the remaining 5 tbsp desiccated coconut. Also, preheat the oven to 350 F / 180 C and line two baking trays with parchment paper or silicon mat.
Place all the cookies on a baking tray, bake for 16-18 minutes, until golden brown.
The cookies will crisp upon cooling, transfer to a wire rack to cool completely, then store in an airtight container. They last for about 2 weeks.