Preheat oven to 350°F. Line a 9x13-inch pan with foil or parchment paper and spray with cooking spray.
Place the baking chocolate and butter in a large, microwave safe bowl. Heat on HIGH power for 2-3 minutes, stirring every 30 seconds, until chocolate mixture is smooth.
Stir in sugar and mix for 30 seconds. Add eggs, vanilla, and cocoa and stir well. Add flour and stir carefully.
Spread batter in prepared pan. Bake about 20-25 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 for up to 3 days or freeze for up to 3 months.