Preheat the oven to 350°F (175°C) and grease a 9×13-inch pan. Mix cake mix, melted butter, and an egg until a thick dough forms, then press it evenly into the pan.
Beat softened cream cheese until smooth, then add pumpkin puree, eggs, melted butter, and vanilla. Mix until creamy, stir in spices, and gradually blend in powdered sugar until fluffy.
Pour the pumpkin mixture over the base, spread evenly, and bake for 45–50 minutes until edges are set and the center stays slightly gooey. Let it cool before slicing.
Dust with powdered sugar and finish with whipped cream, caramel drizzle, or toasted pecans before serving.