Preheat the oven to 350 degrees. Coat a 9 x 13 baking dish coat with butter and a touch of cocoa powder (or flour). Or coat the baking dish with cooking spray.
Combine the dry ingredients by sifting together the flour, cocoa powder, baking powder, baking soda, and salt in a large bowl.
Make the cake batter by combining together the boiling water, shaved chocolate, and espresso powder together; cover and set aside to allow the chocolate to melt completely, about 10 minutes. Use once the water is warm but not hot to the touch.
In a separate bowl, combine the cooled chocolate-water with the sugar, eggs, oil, and vanilla extract. Whisk until well incorporated. Pour the chocolate mixture into the flour mixture and beat, using a mixer, until just combined. Make sure to stop and scrape the bottom and sides of the bowl periodically.
Bake the cake by pouring the batter into the prepared baking dish.
Place into the oven and bake for 25-35 minutes or until the top springs back to the touch, the sides of the cake have pulled slightly, and a wooden tester inserted in the center comes out clean.
Remove from the oven and leave the cake in the pan on a wire rack to cool completely.
Make the frosting by combining the egg yolks, evaporated milk, and brown sugar together in a sauce pan over medium high heat; whisk until well combined. Add the butter and cook, whisking constantly until the mixture thickens, about 10 minutes. Remove from the heat and stir in the vanilla and salt; whisk until well combined. Add the coconut and pecans; stir until well combined. Set aside to cool completely.
Finish the cake by spreading the room temperature frosting on the completely cooled cake evenly. Drizzle a little melted chocolate on top, if desired. Serve the cake from the pan. Enjoy!