Cake:

1 package yellow cake mix
1/2 c. butter
1 egg

Mix all ingredients together and set aside 2/3 cup of batter. Press remainder into a greased 9 x 13 pan.

Bake for 15 to 20 minutes in a 350°F oven until lightly brown.

Top Layer:

1 tsp. vanilla
1/4 c. brown sugar packed
3 eggs, beaten
1 1/2 c. dark brown sugar
1 c. chopped pecans

Combine 2/3 C. reserved cake mix and remaining ingredients except nuts. Pour over first layer; top with pecans.

Bake about 40 minutes at 350°F. Cool and cut.