01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan thoroughly.
02 - In a large mixing bowl, whisk pumpkin puree, sweetened condensed milk, eggs, pumpkin pie spice, granulated sugar, and salt until completely 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 across the surface of the pumpkin mixture without mixing.
05 - Drizzle melted butter evenly over the cake mix, ensuring maximum coverage.
06 - Scatter chopped pecans evenly over the surface, if using.
07 - Bake for 45 to 55 minutes until the top is golden brown and the center is set. The dessert will firm as it cools.
08 - Cool for at least 30 minutes before serving. Serve warm or chilled with optional whipped cream or vanilla ice cream.