Preheat the oven to 350 degrees. Line a baking sheet with parchment paper or a silpat mat.
Combine the flour together with the cocoa powder, baking powder, and salt; mix until well combined.
Beat together in a separate bowl the butter and sugars until creamy.
Add the full egg, yolk, and vanilla; beat until creamy.
Slowly add the flour to the butter mixture - the batter will be thick.
Add the chocolate chips and mix until combined.
Scoop spoonfuls (about 1 ½ tbsp) of the dough onto the baking sheet placing them 2 inches apart.
Place into the oven and bake for 8-10 minutes, or until set.
Remove from the oven and allow them to set for 7-10 minutes before moving them to a wire rack to finish cooling.
Make the frosting by combining the evaporated milk, sugar, egg yolk, and butter in a small saucepan over medium heat. Cook, stirring often for 10 minutes, or until thickened.
Add the coconut, pecans, and vanilla; stir until well combined. Set aside to cool completely.
Once the cookies are cooled completely and the coconut pecan frosting is cooled completely, add a dollop of frosting to each cookie you plan on serving.
If desired, melt some semi sweet melting wafers in the microwave per instructions and drizzle on top of each cookie. Serve with ice cold milk and enjoy.
Store the remaining cookies in a sealed container. Store the frosting in a sealed container in the refrigerator.