Preheat oven to 350º. Prepare baking pan by greasing and flouring a 9x13 inch pan. I used cocoa on my pan instead of flour.
Combine 2 sticks real butter, 1 cup boiling water and 4 Tbsp. cocoa in small sauce pan and bring to a boil.
While waiting for hot mixture to boil, mix 2 cups sugar, 2 cups flour and the salt together. Add dry ingredients to hot mixture. Add 1/2 cup buttermilk and 1 tsp. baking soda together, and add 2 eggs. Mix well. Add nuts if you are using them. Mix all above ingredients together. Pour into prepared pan and bake at 350º for 40 minutes. Cool slightly. Don't overbake.
ICING: Melt 1 stick butter, 4 Tbsp. milk and 4 Tbsp. cocoa together in small pan. Add 1-2 cups powdered sugar to thicken. Add 1 tsp. vanilla extract. Spread icing on slightly cooled brownies. Sprinkle nuts over iced brownies. Cover until ready to serve. This is truly the best brownies I have ever eaten.