Grease bottom only of a 9 x 13-inch pan. Reserve 1 cup cake mix for topping. Combine remaining cake mix, butter and 1 egg. Press into pan.

Prepare filling by combining  can of pumpkin, spice, brown sugar, 2 eggs, and milk until smooth. Pour over crust.

For topping, combine the 1 cup of reserved cake mix, sugar, cinnamon and 1/4 cup butter or margarine. Sprinkle over filling. Bake at 350° for 45 to 50 minutes, until knife inserted near center comes out clean. If desired, serve with whipped topping.