Preheat oven to 350°F (175°C). Grease a 9x9 inch baking pan and line with parchment paper.
In a medium bowl, whisk together sugar, flour, cocoa powder, baking powder, and salt.
Add melted butter, eggs, and vanilla extract to the dry ingredients; stir until smooth.
Pour batter into prepared pan and bake for 30 minutes or until a toothpick inserted comes out with moist crumbs.
While brownies bake, prepare frosting: In a saucepan, combine egg yolks, butter, evaporated milk, and sugar. Cook over medium heat, stirring constantly until thickened.
Remove saucepan from heat; stir in shredded coconut and chopped pecans. Let cool slightly.
Spread frosting evenly over warm brownies. Cool completely before slicing and serving.
Notes
Store brownies in an airtight container for up to 3 days or freeze for longer storage.