In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar together until the mixture is light and fluffy. In a separate bowl, whisk the flour, baking powder, and salt. Gradually add the flour mixture to the butter mixture in three parts, mixing well after each addition and scraping down the sides of the bowl as needed. Add the milk and vanilla extract, mixing until combined and the dough starts to come together in large clumps. Divide the dough in half using your hands, pressing each portion into a compact disk. Wrap the disks tightly in plastic wrap and chill them in the refrigerator for about 1 hour until firm. Preheat the oven to 350°F (175°C). Once chilled, roll each disk on a lightly floured surface to about 1/8-inch thickness. Use a doughnut-shaped cookie cutter (see Kelly’s Notes for alternatives) to cut out as many cookies as possible. Place the cutouts on baking sheets lined with parchment paper or a Silpat mat, and repeat with any remaining dough. Bake the cookies for 10 to 12 minutes, rotating the baking sheet halfway through baking, until the cookies are a pale golden color. Transfer the baked cookies to a wire rack to cool completely.

Spread the shredded coconut evenly on a parchment-lined baking sheet. Toast the coconut in the oven at 350°F (175°C) for about 10 minutes, stirring frequently to ensure even browning and prevent burning (see Kelly’s Notes). Remove the coconut from the oven and set aside. Using a double boiler, melt the caramels, milk, and salt together in a medium saucepan set over a larger pot of simmering water. Stir constantly until the caramels are fully melted and smooth. Remove from heat and stir three-quarters of the caramel mixture into the toasted coconut in a large bowl. Carefully spread the remaining caramel evenly over the cooled cookies, then press portions of the caramel-coconut mixture onto each cookie. Let the cookies rest for 30 minutes to set. If the caramel-coconut mixture becomes too firm to spread, gently warm it again over the double boiler until it softens.

Melt the dark chocolate using a double boiler or microwave until smooth. Dip the bottom of each cookie into the melted chocolate and place it on a wax paper-lined baking sheet. Use a fork to drizzle melted chocolate over the tops of the cookies. Allow the chocolate to fully harden before serving.