The Best Ever Chocolet Sheet Cake

The Best Ever Chocolet Sheet Cake
I have make this cake  for a church group and it is very good! This can also be put in a 13x9" pan for the family!
Ingredients
■FOR THE CAKE:
■2 cups Flour
■2 cups Sugar
■¼ teaspoons Salt
■4 Tablespoons (heaping) Cocoa
■2 sticks Butter
■1 cup Boiling Water
■½ cups Buttermilk
■2 whole Beaten Eggs
■1 teaspoon Baking Soda
■1 teaspoon Vanilla

■FOR FROSTING:
■½ cups Finely Chopped Pecans or Walnuts
■1-¾ stick Butter
■4 Tablespoons (heaping) Cocoa
■6 Tablespoons Milk
■1 teaspoon Vanilla
■1 pound (minus 1/2 Cup) Powdered Sugar

Preparation Instructions
Note: I use an 18×13 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.
Chop pecans or walnuts finely.
 Melt butter in a saucepan. Add cocoa, stir to combine, then turn off heat. Add the milk, vanilla, and powdered sugar. Stir together. Add nuts, stir together, and pour over warm cake.
Cut into squares.  From Pioneer Woman Cooks

Note- When put in a 13x9' pan, poke holes in the cake and then pour the frosting on.You can make a little less frosting for this size