Preheat oven 350. Grease and flour 9x13 pan. Measure out 1 cup of dry cake mix, set aside.
Place remaining cake mix, add ONE egg and the stick of butter and mix until combined. Press the mixture into the pan, evenly and up the sides a little bit. Set aside.
In the same bowl (no need to rinse!) add the pumpkin, 3 remaining eggs, evaporated milk, ONE cup of sugar, cinnamon and pumpkin pie spice. Mix on low until it is combined and then beat for 2 minutes until "fluffy". Pour the mixture on top of the cake base. Set aside.
Combine the reserved cake mix and 1/4 cup sugar in mixing bowl. Cut in the cold butter until combined. Stir in pecans. Sprinkle over pumpkin layer and bake for 65-75 minutes until the cake is set in the middle. Remove from the oven and cool at least 20 minutes before serving. Serve cold or warm with whipped cream or vanilla ice cream.