Mix flour and sugar together in a large bowl.
Bring 1/2 cup butter, oil and water to a boil and pour over flour mixture.
Beat in eggs, 2 teaspoons vanilla, cinnamon, soda and buttermilk.
Pour in greased 11 x 17 inch, pan.
Bake 20 minutes in 350 degree oven.
To make the icing, cream together 1/2 cup butter, 1 teaspoon vanilla and cream cheese.
Blend in powdered sugar, beating until light and fluffy.
Spread over warm cake.