Mix Dough: Beat the butter with an electric mixer for 2 minutes until fluffy. Add the sweetened condensed milk and sugar; mix until combined. Mix in the egg and vanilla, scraping the bowl occasionally.

Combine Dry Ingredients: Add the flour, cocoa powder, baking powder, and salt. Mix on low speed until mostly combined. Finish mixing by hand with a spatula to ensure everything is incorporated.

Chill Dough: Wrap the dough tightly in plastic wrap and refrigerate for at least 1 hour, or overnight.

Preheat Oven: Set the oven to 350°F.

Roll and Cut: Divide the chilled dough into 4 pieces. Roll out one piece at a time to ¼-inch thick on a lightly floured surface. Use cookie cutters to cut shapes and place cookies 1 inch apart on a parchment-lined baking sheet.

Bake: Bake for about 8 minutes, depending on cookie size. When the centers look set and not shiny, they’re done. Repeat with remaining dough. Store baked cookies in an airtight container at room temperature for up to 4 days or freeze for 1-2 months.

Make Filling: In a medium saucepan, combine the sweetened condensed milk, shredded coconut, pecans, butter, and coconut milk (or heavy cream). Cook over medium heat, stirring constantly, for about 10 minutes until thick and chunky.

Cool: Transfer the filling to a bowl and let it cool completely at room temperature. It can be stored at room temperature for up to a day.

Fill Cookies: Place the coconut filling in a piping bag with a round tip. Pipe filling onto the bottom side of a cookie, then top with another cookie to make a sandwich.

Add Toppings: Melt the chocolate and either dip the cookies or drizzle the chocolate on top. Sprinkle with shredded coconut or chopped pecans while the chocolate is still wet.