1Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch pan.
Reserve 2/3 cup cake mix.
Mix together remaining cake mix, margarine, and 1 egg. Pat in prepared pan.
Bake at 350 degrees F (175 degrees C) for 15-20 minutes or until golden brown.
Beat together 3 eggs, vanilla, reserved 2/3 cup cake mix, corn syrup, and brown sugar. Pour on cake in pan. Sprinkle pecans on top.
Bake at 350 degrees F (175 degrees C) for 30-35 minutes.