In a saucepan, melt:
2 sticks butter (not unsalted) melt then stir in cocoa
Add 4 heaping tablespoons cocoa. Stir together
Add 1 cup boiling water, allow mixture to boil for 30 seconds, then turn off heat.
Turn off heat and set aside
Combine in a mixing bowl:
2 cups flour
2 cups sugar
1/4 teaspoon salt
Pour chocolate mixture over flour mixture. Stir slightly just allowing chocolate to cool.
In a measuring cup, pour 1/2 cup buttermilk.
Add:
2 beaten eggs
1 teaspoon baking soda
1 teaspoon vanilla
Stir buttermilk mixture into butter/chocolate mixture. Pour into ungreased sheet cake pan and bake at 350 degrees for 20 minutes.
While cake is baking, make icing.
Chop 1/2 cup pecans finely.
Melt 1 3/4 sticks butter in a saucepan.
Add 4 heaping tablespoons cocoa, stir to combine, let bubble for 30 seconds then turn off heat.
Add:
6 tablespoons milk
1 teaspoon vanilla
1 pound minus 1/2 cup powdered sugar
Stir together.
Add pecans, stir together, and pour over warm cake.