Preheat oven to 350 degrees F. Mix flour, sugar and cinnamon together in a large bowl. In a saucepan, bring cocoa, water and oil to a boil. Pour over flour mixture and mix 1 minute, scraping bowl. Dissolve soda in buttermilk, adding to mixture in bowl along with eggs and vanilla. Mix an additional 2 minutes. Pour into a greased and floured 10 x 15 x 1-inch jelly-roll pan. Bake 20 minutes. Cool in pan before removing.

Icing: In a saucepan, bring cocoa, butter or margarine and milk to a boil. Remove from heat and beat in sugar and nuts. Frost cake while still warm.

Courtesy of Wheat Foods Council.