Preheat oven to 325 degrees.
Sift flour and sugar together, put in large bowl.
Mix butter, oil, cocoa, water and salt in a saucepan and bring to a boil; pour over flour and sugar mixture and beat by hand with a wooden spoon.
Stir in buttermilk, cinnamon, eggs, soda and vanilla.
Pour into a greased jellyroll pan and bake at 325 degrees for about 20 minutes or just until set.
For the Icing: Bring butter, cocoa and milk to a light boil; remove from heat and beat in 1 pound of powdered sugar; stir in vanilla and pecans.
Pour over cake while cake is still warm.