Preheat oven to 350 degrees F (175 degrees C). Lightly grease and flour a 13 x 9 inch cake pan.
In a large bowl, blend cake mix, water, egg substitute, vanilla extract and butter flavor on low speed until moistened. Beat on medium speed for 2 minutes.
Bake for 25 to 30 minutes or until toothpick inserted in center comes out clean. Cool and cut into squares.
