Pecan Surprise Bars

1 yellow cake mix {reserve 2/3 c.}
1 egg
1/2 c. butter {melted}
1 bag chopped pecans {about 2 cups}
2/3 c. cake mix
1 1/2 c. dark brown corn syrup
3 eggs
1/2 c. brown sugar
1 t. vanilla

Spray 13x9 inch pan and preheat oven to 350 degrees. For the base mix the cake mix, butter egg together until combined and press into pan. Bake for 15 to 20 mins. Prepare the filling by mixing all ingredients and pour over the partially baked crust. Sprinkle with the chopped pecans. Bake for 30 to 35 mins. Cool and cut.