Upside-Down Pumpkin Cake “Pie” is a favorite pumpkin pie substitute from the 1990s. It is an easy pumpkin dessert that is like both a cake and a pie. The pumpkin pie part on the bottom, and a slightly crunchy, super buttery cake mix crust on top! It is really more like a streusel. Try serving this instead of the traditional pumpkin pie for your next Thanksgiving dinner. I know that your family will love this Upside-Down Pumpkin Cake!