Preheat your oven to 350°F (175°C) and prepare a 9x13-inch baking dish by coating it generously with nonstick cooking spray.

In a medium mixing bowl, whisk together the pumpkin puree, evaporated milk, eggs, sugar, and cinnamon until the mixture is smooth and fully blended; it will have a liquid consistency.

Pour this pumpkin mixture into the prepared baking dish, spreading it out evenly.

Sprinkle the dry spice cake mix evenly over the pumpkin mixture, ensuring complete coverage.

Drizzle the melted butter evenly over the top of the dry cake mix, covering as much of the surface as possible.

Place the baking dish in the preheated oven and bake for 55 to 60 minutes, or until the cake is golden brown and set around the edges. The center may still be slightly jiggly when you remove it from the oven but will continue to firm up as it cools.

Allow the cake to cool in the pan for at least 30 minutes before slicing and serving to let it fully set.

Enjoy this deliciously simple pumpkin dump cake, perfect for fall gatherings or a cozy dessert at home!