01 - Preheat oven to 350°F. Lightly grease a 9x13-inch baking pan and set aside.
02 - Whisk pumpkin puree, sweetened condensed milk, eggs, pumpkin pie spice, granulated sugar, and salt in a large mixing bowl until the mixture is fully blended and smooth.
03 - Pour the pumpkin mixture evenly into the prepared baking pan, smoothing the surface.
04 - Evenly sprinkle the dry yellow cake mix across the surface of the pumpkin layer without mixing.
05 - Drizzle the melted butter over the entire cake mix, ensuring even coverage.
06 - Distribute chopped pecans evenly over the top, if desired.
07 - Bake for 45 to 55 minutes or until the top is golden brown and the center is set.
08 - Allow to cool in the pan for at least 30 minutes before slicing. Serve warm or chilled with whipped cream or vanilla ice cream as desired.