- Cake: Combine butter, water, and cocoa in saucepan over medium heat; heat until butter melts. 
- Add sugar, flour, salt, eggs, soda, sour cream, and vanilla; mix well. 
- Pour into a 15x10x1-inch jelly roll pan. Bake at 350° for 20 minutes. 
- Spread frosting over hot cake and sprinkle with chopped pecans.