Preheat your oven to 350°F (175°C). Grease an 8x8 inch baking pan or line it with parchment paper.
In a medium bowl, whisk together the melted butter and granulated sugar until combined. Then add the eggs and vanilla extract, mixing until smooth.
Sift in the cocoa powder, flour, salt, and baking powder. Stir until just combined; be careful not to overmix.
Pour the brownie batter into the prepared baking pan, spreading it evenly to cover the bottom.
In a separate bowl, beat the softened cream cheese with a mixer until smooth. Add the pumpkin puree, powdered sugar, egg, vanilla extract, and pumpkin pie spice. Mix until well combined and creamy.
Pour the pumpkin cheesecake mixture over the brownie layer in the baking pan. Gently swirl it with a knife to create a marbled effect, if desired.
Bake in the preheated oven for 30-35 minutes or until the cheesecake layer is set and lightly golden. A toothpick inserted into the brownie layer should come out with a few moist crumbs.
Allow the bars to cool in the pan on a wire rack. Once cooled, chill in the refrigerator for at least 2 hours for easier cutting.
When ready to serve, cut into squares or bars and enjoy!
Notes
Serve the bars on a platter dusted with powdered sugar and garnish with a sprinkle of cinnamon or a dollop of whipped cream on each bar.