01 - In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until thoroughly blended. Set aside.
02 - In a large mixing bowl, beat the unsalted butter and granulated sugar with an electric mixer on medium speed until the mixture is light and fluffy, about 2 minutes.
03 - Add the eggs, one at a time, beating well after each addition. Mix in the vanilla extract, key lime zest, and key lime juice until fully incorporated.
04 - Gradually add the dry ingredients to the wet mixture, blending just until combined. Do not overmix.
05 - Using a spatula, gently fold in the sweetened shredded coconut to distribute evenly throughout the dough.
06 - Cover the bowl with plastic wrap and chill the dough in the refrigerator for at least 30 minutes to allow flavors to develop and dough to firm up.
07 - Preheat the oven to 350°F. Line baking sheets with parchment paper for even baking and minimal sticking.
08 - Scoop tablespoon-sized portions of dough, roll into balls using your hands, then coat each ball generously in powdered sugar.
09 - Place coated dough balls 2 inches apart on the prepared baking sheets. Bake for 10 to 12 minutes, or until the edges are set and tops exhibit a crinkled appearance.
10 - Let the cookies rest on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.