Preheat oven to 350 degrees. Line a 9x13” pan with foil and spray with cooking spray.
Place the two baking chocolates and butter in a large, microwave safe bowl. Heat on HIGH power for 2-3 minutes, stirring every 30 seconds, until chocolate is smooth. Stir in sugar. Add eggs, vanilla, and cocoa and stir well. Add flour and stir carefully.
Spread batter in prepared pan. Bake about 25 minutes, until a toothpick 2 inches from the outside of the pan comes out clean. Let cool before frosting.
Make the frosting: Combine the evaporated milk, sugar, egg yolks, and butter in a medium saucepan. Cook over medium heat, stirring constantly, until the butter has melted and the mixture thickens and bubbles. Once it bubbles, reduce heat to low and cook for 2 more minutes. Remove the pan from the heat and stir in the vanilla, coconut, and pecans. Cool about 1 hour, until the mixture is spreadable.
Spread frosting over the top of the cooled brownies. Cut into squares. Store in refrigerator.