Preheat: Heat oven to 350°F, line and grease pans.
Melt Chocolate: Mix boiling water with chocolate until smooth.
Dry Mix: Whisk flour, baking soda, and salt.
Cream: Beat butter and sugar until fluffy.
Add Eggs: Mix in eggs one at a time.
Add Chocolate: Stir in melted chocolate and vanilla.
Combine: Alternate flour mixture with buttermilk.
Bake: Divide into pans and bake 30 minutes.
Frosting: Cook evaporated milk, sugar, butter, yolks, and salt 12 minutes.
Finish Frosting: Add coconut, pecans, and vanilla; cool.
Assemble: Layer and frost cake.
