Preheat oven to 250 degrees F (120 degrees C). Spray a 10-inch fluted tube pan (such as a Bundt(R)) with cooking spray.
Mix white cake mix, pumpkin, butterscotch pudding mix, eggs, water, canola oil, and pumpkin pie spice in a bowl until all ingredients are thoroughly combined and the batter is smooth. Pour batter into prepared cake pan.
Bake in the preheated oven until a toothpick inserted into the center of the cake comes out with moist crumbs, about 1 hour and 10 minutes. Let cake cool in the pan for 15 minutes before inverting onto a serving dish to remove cake from pan.