PW Chocolate Sheet Cake

I love this recipe from Pioneer Woman  (linked in title below)

Pioneer Woman Chocolate Sheet Cake
Combine in a mixing bowl:
2 cups flour
2 cups sugar
1/4 teaspoon salt

In a saucepan, melt:
2 sticks butter
Add 4 heaping tablespoons cocoa. Stir together.
Add 1 cup boiling water, allow mixture to boil for 30 seconds, then turn off heat. Pour over flour mixture, and stir lightly to cool.

In 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 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, then turn off heat.
Add:
6 tablespoons milk
1 teaspoon vanilla
1 lb minus 1/2 cup powdered sugar
Stir together.
Add pecans, stir together, and pour over warm cake.

This is an extremely rich, but yummy cake.  Cut in small pieces!