Make the Brownie Base:

1. Preheat oven to 350F. Line an 8-inch square baking pan with parchment paper or greased foil.
2. In a small saucepan set over medium-low heat, melt the butter and chocolate together until smooth, stirring constantly. Remove from heat and scrape into a medium mixing bowl. Stir in the sugar, vanilla and salt, then beat in the eggs one at a time, mixing well after each addition. Stir in the flour and mix until just barely combined.

Prepare the Pumpkin Swirl Batter:

1. In a second mixing bowl, beat together cream cheese and sugar until combined. Stir in the pumpkin, egg and vanilla, and beat until smooth. Stir in the remaining ingredients, and set aside.

Assemble the Brownies:

1. Spread half of the brownie batter into the prepared baking pan. Drop alternating spoonfuls of the pumpkin filling and the remaining brownie batter onto the brownie layer. Run a sharp knife through the batter in a zig zag sort of motion to swirl the brownie batter and pumpkin filling together.
2. Bake in preheated oven until the edges are set and the middle is still a little wobbly, about 25-30 minutes. Let cool in the pan about 15 minutes, then use the edges of the parchment to lift out the brownies and transfer to a wire rack to cool completely.
3. Cut the cooled brownies into squares, and store in an airtight container for up to 3 days (assuming they last that long).