Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking pan.

In a mixing bowl, combine yellow cake mix, melted butter, and 2 eggs until a thick batter forms, then press into the pan.

Add softened cream cheese, remaining eggs, pumpkin puree, vanilla, pumpkin pie spice, and cinnamon to the bowl and mix until smooth.

Sift in powdered sugar gradually while mixing until fully incorporated and silky.

Pour filling over the crust and bake for 35-40 minutes until the top is set and crackled.

Cool completely on a wire rack before slicing into bars.

Slice into squares and serve warm or chilled, optionally with whipped cream.