Preheat the oven to 375 degrees F. Spray a 9x13 inch baking dish with nonstick baking spray.
In a bowl, whisk together the cocoa, salt and baking powder.
Hear the butter in a saucepan over medium heat until the it melts. Whisk in the sugar until it's smooth. Whisk in the cocoa powder mixture until combined. Let it cool for 5 to 10 minutes. Whisk in the vanilla extract.
Whisk in the eggs until smooth, then whisk in the flour. Pour half of the mixture into the baking dish.
Make the pumpkin layer by beating the cream cheese in an electric mixer until it's smooth and creamy. Beat in the rest of the ingredients until you have a smooth pumpkin batter and no lumps remain.
Top the brownie batter in the dish with the pumpkin batter. Drop the rest of the brownie batter into the pumpkin batter, using a knife or skewer to swirl it together.
Bake the brownies for 40 to 45 minutes, or until a toothpick inserted in the center comes out clean. Let cool completely before slicing!