Preheat your oven to 350°F.
Grease a 9x13 inch baking dish.
In a large bowl, mix together the pumpkin puree, evaporated milk, eggs, sugar, and spices. Stir until smooth.
Pour the mixture into your prepared baking dish.
Sprinkle the dry cake mix evenly over the top of the pumpkin mixture. Don’t mix it in—just let it sit on top.
Drizzle the melted butter over the cake mix. Make sure to cover as much as possible.
If you’re adding pecans, sprinkle them over the top for an extra bit of crunch.
Bake for 50-60 minutes until the top is golden brown and the pumpkin layer has set.