01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan.
02 - In a large mixing bowl, whisk together pumpkin puree, sweetened condensed milk, eggs, pumpkin pie spice, granulated sugar, and salt until smooth.
03 - Pour the pumpkin mixture into the prepared baking pan and spread into an even layer.
04 - Sprinkle the dry yellow cake mix evenly over the pumpkin layer without stirring.
05 - Drizzle melted butter evenly over the surface of the cake mix, covering as much as possible. Scatter chopped pecans over the top if desired.
06 - Bake for 45 to 55 minutes until the top is golden brown and the center is set.
07 - Allow to cool for at least 30 minutes before slicing. Serve warm or chilled, optionally with whipped cream or vanilla ice cream.