01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan to prevent sticking.
02 - In a large mixing bowl, whisk together pumpkin puree, sweetened condensed milk, eggs, pumpkin pie spice, granulated sugar, and salt until the mixture is smooth and fully combined.
03 - Pour the prepared pumpkin mixture into the greased baking pan and spread in an even layer.
04 - Sprinkle the dry yellow cake mix evenly over the pumpkin layer, being careful not to stir or mix.
05 - Drizzle melted butter evenly across the surface, aiming to moisten as much of the cake mix as possible.
06 - Evenly scatter chopped pecans over the top, if using.
07 - Bake in preheated oven for 45–55 minutes or until the top is golden brown and the center is set. The texture will continue to firm as it cools.
08 - Remove from oven and allow to cool at least 30 minutes before serving. Serve warm or chilled, optionally topped with whipped cream or vanilla ice cream.