Preheat the oven to 375 degrees.
Add the butter and vanilla extract to the bowl of a stand mixer fitted with the paddle attachment. Cream together until smooth. In a separate bowl, sift together confectioners sugar, flour, cornstarch and salt. Add the sugar mixture to the butter mixture slowly, by the spoonful, with the mixer running on low. Fold in the coconut and the dark chocolate chips.
Use a small cookie scoop (or ice cream scoop) to drop the cookies on a parchment-lined cookie sheet, leaving about two inches between each ball.
Press each one down gently with your hand or a spoon to make an even-height cookie round. Cook in the preheated oven for about 12 minutes.
Transfer cookies to a cooling rack and allow to cool completely. Store in an airtight container for up to four days.