### Instructions
1. **Preheat and Prep:** Preheat your oven to 350°F (175°C). Lightly grease a 9×13 inch baking pan with non-stick spray or butter.
2. **Make the Crust:** In a medium bowl, combine the yellow cake mix, egg, and melted butter. Mix until well combined and a soft dough forms. Press the dough evenly into the bottom of the prepared baking pan.
3. **Prepare the Filling:** In a large bowl, using an electric mixer, beat the softened cream cheese until smooth and creamy.
4. **Add Pumpkin and Vanilla:** Add the pumpkin puree and vanilla extract to the cream cheese mixture and beat until thoroughly combined.
5. **Incorporate Egg and Butter:** Beat in the egg and melted butter until just incorporated.
6. **Mix in Powdered Sugar and Spice:** Gradually add the powdered sugar and pumpkin pie spice, beating on low speed until smooth. Scrape down the sides of the bowl as needed. The mixture will be thick.
7. **Assemble the Bars:** Carefully pour the pumpkin filling over the crust in the baking pan, spreading it evenly with a spatula.
8. **Bake:** Bake for 40-50 minutes, or until the edges are golden brown and the center is set but still slightly jiggly. A toothpick inserted into the center should come out with moist crumbs, not wet batter.
9. **Cool and Serve:** Let the bars cool completely on a wire rack before cutting into squares. For an extra touch, dust with a little extra powdered sugar before serving.
### Short Tips
* **Room Temperature Cream Cheese:** Ensure your cream cheese is at room temperature for a smooth, lump-free filling.
* **Don’t Overbake:** These bars are meant to be gooey, so avoid overbaking. The center should still have a slight jiggle.
* **Storage:** Store leftover bars in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to a week.
* **Spice It Up:** If you love a stronger pumpkin spice flavor, feel free to add an extra 1/2 teaspoon of pumpkin pie spice to the filling.
* **Serving Suggestion:** Serve warm with a dollop of whipped cream or a scoop of vanilla ice cream for an extra indulgent treat!
