Cookies
Preheat oven to 350°F (177°C). Line two baking sheets with parchment paper.
Whisk together flour, cocoa powder, baking powder, and salt; set aside.
Melt chocolate and butter together in microwave-safe bowl in 15-second intervals, stirring until smooth. Let cool slightly.
In a large bowl, whisk eggs, granulated sugar, brown sugar, and vanilla until combined.
Add melted chocolate mixture and stir well.
Gradually stir in dry ingredients until just combined.
Use a 3-tablespoon scoop to portion dough onto baking sheets.
Bake for 12 minutes or until cooked through. Remove and cool.
Frosting
In a saucepan, combine evaporated milk, granulated sugar, egg yolks, butter, and salt.
Cook over low-medium heat, stirring constantly until thickened (about 6 minutes).
Remove from heat and stir in vanilla, coconut, and pecans.
Spread about 2 tablespoons of frosting on each cooled cookie.