1. Preheat oven to 350°F (175°C). Grease and line three 8-inch (or two 9-inch) round cake pans. 2. In a bowl, whisk together flour, cocoa, baking soda, baking powder, and salt. 3. In a large bowl, beat sugar, oil, eggs, and vanilla until smooth. Alternate adding dry ingredients and buttermilk, mixing until just combined. Stir in hot water. 4. Divide batter among pans and bake 25–30 minutes, or until a toothpick comes out clean. Cool completely. 5. For the frosting: In a saucepan, cook brown sugar, evaporated milk, butter, and egg yolks over medium heat, stirring constantly, until thickened (10–12 minutes). 6. Remove from heat and stir in vanilla, coconut, and pecans. Let cool slightly. 7. Assemble cake by layering with frosting between and on top. Garnish with extra coconut or pecans if desired.