Preheat oven to 350 degrees F (175 degrees C). Grease one 9 x13 inch baking pan.
Step 2
Reserve 2/3 cup of the cake mix and set aside. In a large bowl combine the remaining cake mix, melted butter and 1 egg. Mix until crumbly then press mixture into the prepared pan.
Step 3
Bake at 350 degrees F (175 degrees C) for 15 to 20 minutes, until light golden brown.
Step 4
Combine the reserved 2/3 cup cake mix, brown sugar, corn syrup, vanilla and 3 eggs. Beat at medium speed for 1 to 2 minutes. Pour filling over the baked crust and sprinkle with pecans.
Step 5
Return to oven and bake for an additional 30 to 35 minutes, until the filling is set. Cool and cut into 36 bars.