Grease a 9x13 pan. Preheat oven to 400 degrees F.
For the crust, mix 1 box dry yellow cake mix, reserving 1 cup for the topping, butter and egg. Press into prepared pan.
For the filling, mix pumpkin, eggs, sugar, nutmeg, cinnamon, and evaporated milk. Add this over mixture the crust. This mixture can be substituted with a can of pumpkin pie mix.
For the topping, combine the reserved cake mix, sugar, cinnamon, softened butter and nuts, if desired. Sprinkle over the cake.
Bake at 400° for 10 minutes. Then reduce oven heat to 350° for 30-35 minutes.
When serving this can be topped with cool whip or ice cream.