Sift or mix flour, salt, and baking soda together in a bowl. Set aside.
Melt chocolate in a small bowl in the microwave for 20 seconds at a time. It will take a few times to get it all the way melted, but it's really important not to burn the chocolate. So keep it in short increments, stirring each time. When chocolate is fully melted, set aside to cool a bit.
In a large mixing bowl, cream together butter and sugar until light and fluffy.
Add yolks, one at a time, beating well after each addition.
Mix in cooled chocolate and vanilla.
Add flour mixture alternately with buttermilk (So add about a third of the flour mixture, followed by 1/3 cup of milk, and continue until both are entire mixed in). Beat after each addition until smooth.
Fold in stiff egg whites.
Bake at 350° in a lined and greased cake pan for 30-40 minutes, until cooked through. This recipe will make about three 8-inch layers or two 9-in layers.
Directions for Coconut Pecan Frosting:
Mix all ingredients, except coconut and pecans, together in a medium to large saucepan.
Cook and stir over medium heat until thickened, about 12 minutes. Frosting will thicken a tiny bit more after cooling. Remove from heat when frosting has thickened.
Add coconut and pecans. Stir to incorporate. Allow frosting and cake to fully cool before frosting the completely cooled cake.