Preheat your oven to 350 degrees Fahrenheit. Line a 9×9 baking pan with foil or parchment paper for easy removal after baking. Don't forget to spray the bottom of the lined pan with non-stick oil to prevent sticking!
In a heavy pot on low heat, melt butter and chocolate together, stirring continuously until the mixture is smooth and melted. Remove from the heat and let it cool slightly.
In a large mixing bowl, use an electric mixer to combine sugar and eggs. Beat them until they are very well combined, creating a fluffy mixture.
Add in flour, baking powder, and salt to the egg mixture. Stir gently until just combined, being careful not to overmix. The batter should remain thick and fudgy.
Divide the egg, sugar, and flour mixture evenly into two separate bowls. To one bowl, add the melted chocolate mixture. Stir until fully combined.
In the other bowl, add the pumpkin puree, vegetable oil, cinnamon, and pumpkin pie spice. Mix until everything is well blended.
Now comes the fun part! Layer the pumpkin and brownie batters into the prepared pan. Use a knife to gently swirl the two batters together, creating a beautiful marbled effect.
If you like, sprinkle chocolate chips on top of the batter for that extra chocolatey touch.
Bake in the preheated oven for approximately 40 to 45 minutes. To check for doneness, insert a toothpick into the center; it should come out almost clean.
Once baked, allow the brownies to cool in the pan on a wire rack before cutting them into squares. Enjoy your Pumpkin Brownies warm or at room temperature!
