Preheat oven to 325 degrees. Line an 8 by 8-inch baking dish with aluminum foil, leaving a two-inch over hang on two sides. Butter foil and lightly dust with flour, shaking out excess flour, set aside.
In a mixing bowl, whisk eggs until frothy and slightly pale, about 1 minute. Add granulated sugar, brown sugar and salt and whisk until well combined. Stir in vanilla.
Sift cocoa and flour over top, pour in melted butter, and using a wooden spoon, stir until combined (it will be lightly lumpy).
Pour batter into prepared baking dish and spread into an even layer. Bake in preheated oven until toothpick inserted into center comes out with a thin coat of batter, about 35 - 40 minutes. Cool completely on a wire rack.
For the topping:
In a medium saucepan combine, evaporated milk, egg yolks, brown sugar and butter. Cook mixture over medium heat, stirring constantly, until thickened, about 10 minutes. Remove from heat.
Stir in vanilla, then mix in shredded coconut and chopped pecans. Allow mixture to cool to room temperature about 30 minutes then spread over cooled brownies (for cleaner cut brownies cover and chill in freezer, about 15 minutes).