1Heat oven to 350°F (325°F for dark or nonstick pan). Spray bottom and sides of 1 15x10x1-inch pan with baking spray with flour.
In large bowl, beat cake mix, sour cream, water, cocoa, butter and eggs with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally. Pour into pan.
Bake 18 to 22 minutes or until toothpick inserted in center comes out clean.
Cool about 45 minutes.
1 ¾ Sticks butter 6 T milk 1 t. vanilla extract
4 heaping T. cocoa 1 lb. powdered sugar ½ C. chopped pecans
Melt butter in saucepan over med. heat. Add cocoa powder & stir til smooth. Add milk & vanilla. Add powder sugar. Stir together. Dump pecans & stir til well combined. Pour over warm cake.