1. Preheat the oven to 350°F (175°C) and line a 9×9-inch baking pan with parchment paper or grease it.

2. Whisk melted butter with granulated sugar and brown sugar until smooth and glossy.

3. Stir in eggs and vanilla extract until fully combined.

4. Sift together flour, cocoa powder, salt, and baking powder and fold into the wet mixture until just combined.

5. Reserve 2 tablespoons of the brownie batter for the swirl and spread the remaining batter evenly in the prepared pan.

6. Beat cream cheese until smooth, then add pumpkin puree, granulated sugar, egg, cinnamon, nutmeg, and cloves and mix until velvety.

7. Pour the pumpkin cheesecake mixture over the brownie base and smooth into an even layer.

8. Drop the reserved brownie batter by spoonfuls onto the pumpkin layer.

9. Use a toothpick to gently swirl the layers in a figure-eight motion to create a marbled effect.

10. Bake for 35 to 40 minutes until the edges are set and the center is slightly jiggly.

11. Allow the bars to cool completely in the pan, then chill in the refrigerator for at least one hour.

12. Use a sharp knife wiped clean between cuts to slice into 16 bars and serve.