Sift flour, sugar and salt into bowl. In sauce pan: 2 sticks butter, 1/4 cup cocoa, 1 cup water. Bring to boil. Pour over ingredients in bowl. Add sour cream. add baking soda, eggs and 1 tsp vanilla. Mix well and pour into 18X12X1 pan. Bake 25-30 minutes at 350. Spread with icing while cake is still warm.
Icing: 1 butter, 1/3 cup milk, 1/4 cup cocoa. Bring to hard boil for 1-2 minutes. Pour over box confectioners sugar. Add 1 tsp vanilla and 1 cup nuts.