Lunchroom Lady Iced Brownies

Why I Love This Recipe
This recipe popped up quite a bit on Face Book for a while. It was touted as being a '50 year old recipe.' I don't know about that, but it is a good, old-fashioned brownie recipe. This version of the recipe has very little instructions, but the brownies turn out fine, and the simplicity is a welcomed change.
Ingredients You'll Need
Brownies
1 cup butter (2 sticks), softened
1/2 cup cocoa
2 cups flour
2 cups sugar
4 eggs
4 tsp vanilla
1 cup chopped nuts (walnuts or pecans)
Icing
1/4 cup softened butter (1/2 stick)
1/4 cup evaporated milk (regular milk is fine)
1/4 cup cocoa
3 cups powdered sugar
dash salt
Directions
For Brownies
Preheat oven to 350.
Mix all ingredients together.
Pour into 9 X 13 pan.
Bake 20 to 25 minutes. Check at 20 minutes.
For Icing:
Mix all ingredients together.
Frost cooled brownies.