Combine the sugar, butter, evaporated milk, and egg yolks for the filling in a lareg saucepan.
Cook over medium heat, stirring, until thickened, about 15 minutes.
Cool for about 20 minutes, then fold in the coconut, pecans, and vanilla.
Add the icing to the fridge.
Pre-heat the oven to 350°F.
Butter and flour three 10-inch round cake pans.
Sift the flour, cocoa, salt, baking soda, baking powder, and sugar in a large bowl and whisk to combine.
In another bowl, whisk together the eggs, buttermilk, and coffee.
Stir the egg mixture into the dry ingredients.
Add the melted butter and stir to combine.
Divide the batter among the prepared pans.
Bake until to firm to the touch, and a toothpick inserted in comes out clean, about 35 minutes.
Remove the cakes and let cool in the pans for 10 minutes, then run a knife around the rim of the pans, then invert the cakes onto a rack, and cool completely.
Place the bottom cake on your serving dish.
Take the icing from the fridge, and then, using a plastic spatula, spread the icing on the bottom layer of the cake, then place the second cake layer on top.
Frost the top of the 2nd layer, then place the 3rd layer on top of it.
Then, cover the top and sides with the remaining icing.
To serve, I like to cut the cake with a long sharp knife, and the wipe it off with hot water, making the next slice that much easier to cut!