BASE:

1 box yellow cake mix (reserve 1 c.)
1 egg
1 stick butter, melted

FILLING:

3 eggs
2/3 c. milk
3/4 c. sugar
2 tsp. cinnamon
1 lg. can solid pack pumpkin

TOPPING:

1/4 c. sugar
2 tbsp. butter, melted
2 tsp. cinnamon
Reserved cake mix

Beat base ingredients with fork and press into 9 x 13 inch cake pan. Beat together filling ingredients and pour over base mixture. Mix topping ingredients and sprinkle on top of filling. Bake at 400 degrees for 10 minutes, then lower to 350 degrees for 35 minutes.