Ingredients for cake:
2 c. flour
2 c. sugar
1/4 tsp. salt
4 tbsp. (heaping) cocoa
2 sticks butter
1 c. boiling water
1/2 c. buttermilk
2 whole beaten eggs
1 tsp. baking soda
1 tsp. vanilla
For the Frosting:
1/2 c. finely chopped pecans
1 3/4 stick butter
4 tbsp. (heaping) cocoa
6 tbsp. milk
1 tsp. vanilla
1 lb. (minus 1/2 cup) powdered sugar

Use an 18x13 sheet cake pan. 
In a mixing bowl, combine flour, sugar, and salt. 
In a saucepan, melt butter. Add cocoa. Stir together. Add boiling water, allow mixture to boil for 30 seconds, then turn off heat. 

Pour over flour mixture, and stir lightly to cool. 
In a measuring cup, pour the buttermilk and add beaten eggs, baking soda, and 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 the icing. 

Melt butter in a saucepan. Add cocoa, stir to combine, then turn off heat. Add the milk, vanilla, and powdered sugar. Stir together. Add the pecans, stir together, and pour over warm cake.