To begin, preheat your oven to 350 and line a 9x9 pan with parchment paper (with two sides sticking out for easy removal).
To a large mixing bowl, add your butter and sugar and blend them together with a mixer till creamy. Add your eggs and vanilla and whisk in briefly. To the same bowl, add your flour and salt. Add your cocoa powder through a fine mesh sieve. Stir all of your ingredients together till you have a smooth, thick brownie batter.
Reserve 1/3 cup of brownie batter, and set aside. Pour the rest of your brownie batter into your pan and spread into an even layer on the bottom of the pan.
To a medium mixing bowl, add your cream cheese and blend with a mixer till creamy. Add your pumpkin puree, sugar, flour, pumpkin pie spice, and vanilla and blend till smooth. Add your egg and blend in briefly (don't over blend it!).
Pour your pumpkin cheesecake mixture over your brownie batter, and spread gently into an even layer across the pan.
With the 1/3 cup of remaining brownie batter, take small spoonfuls and dollop them around on top of the pumpkin cheesecake layer. Use a toothpick and gently swirl the brown batter around, several times for each dollop.
Bake in the oven for 30-35 minutes, or till a toothpick inserted comes out clean (and the cheesecake layer should only wiggle a bit when gently shaking the pan).
Let cool for 30 minutes, then cover and put them in the fridge till cooled entirely.
Slice and devour!
Stored in an airtight container in the fridge these taste best within the first 5-6 days.