Cream together the softened unsalted butter and 1/3 cup of granulated sugar until light and fluffy, about 3-4 minutes. Add the milk and vanilla extract, mixing until well combined.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add the dry mixture to the wet ingredients, mixing until a soft dough forms.
Preheat your oven to 350°F (175°C). Roll the dough out on a floured surface to about 1/4 inch thick. Use a cookie cutter to cut out shapes, ensuring to cut a small hole in the center of each cookie. Place on a parchment-lined baking sheet and bake for 10-12 minutes, or until golden brown.
Combine the shredded coconut with 1/4 cup of granulated sugar and 1 teaspoon of cinnamon. Once the cookies have cooled, spread a layer of dulce de leche over each cookie and top with the coconut mixture.
Melt the dark chocolate and drizzle it over the coconut-topped cookies, allowing it to set for a few minutes.
