Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

In a medium bowl, sift together the flour, cocoa powder, baking powder, and salt.

In the bowl of an electric mixer, beat the butter, brown sugar, and granulated sugar on medium-high speed until well combined and smooth.

Add the egg, egg yolk, and vanilla and mix until combined.

On low speed, gradually add the flour mixture. Fold in the chocolate chips using a spatula.

Using a 1.5-Tablespoon spring-loaded cookie scoop, drop the dough onto the prepared baking sheets.

Bake for about 10 minutes, or until the cookies are set. Let them cool on the baking sheets for 10 minutes before transferring to wire racks to cool completely.

In a small saucepan over medium heat, combine the evaporated milk, sugar, egg yolk, and butter. Cook, stirring frequently, until the mixture thickens, about 10 minutes.

Remove from heat and stir in the vanilla, shredded coconut, and chopped pecans. Let the mixture cool until it thickens enough to spread on top of the cookies.

Spread the coconut pecan topping over each cooled cookie. Drizzle the melted chocolate over the top of each cookie.

Allow the cookies to set for at least 15 minutes before serving.