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