Preheat oven to 350 degrees. Line a square 9x9" baking dish with a parchment paper sling or spray with baking spray.

In a large microwave-safe bowl, combine the bittersweet chocolate and butter. Microwave on high in 20-30 second bursts, stirring well between bursts of heat until melted and smooth. Whisk in cocoa powder.

Add granulated sugar and brown sugar, whisking well to combine. Add eggs and vanilla, beating well either by hand with a whisk or using an electric mixer.

Sprinkle the flour and salt over the brownie batter and gently stir it in with a wooden spoon or spatula. Stir in chocolate chips.

Pour the brownie batter into the prepared baking dish and spread into the corners. The batter will be thick.

Bake for 30 to 35 minutes, until a toothpick inserted into the center of the brownies comes out mostly clean with only a few crumbs attached. Be sure not to overbake.

Cool completely before topping with coconut pecan frosting.

Heat the granulated sugar, brown sugar, evaporated milk, butter, and egg yolks in a medium saucepan over medium heat until thick and golden brown, about 5 minutes. Be sure to stir constantly so as not to scramble the eggs.

Remove from the heat and add coconut, pecans, and vanilla. The frosting will continue to thicken as it cools. Cool for at least 30 minutes until thick enough to spread on top of the brownies.

Store the brownies in an airtight container for up to 5 days on the counter or in the fridge.