Preheat your oven to 350°F and grease or line an 8x8-inch baking dish.
Prepare the brownie mix according to the package directions and pour it into the prepared pan. Smooth out the top.
In a separate bowl, mix together the pumpkin, brown sugar, pumpkin pie spice, cinnamon, vanilla, and egg until well blended.
Carefully spoon the pumpkin mixture over the brownie batter and spread it evenly.
Bake for about 45-50 minutes, or until the center is set and a toothpick comes out mostly clean (a little fudgy is okay).
Let cool completely before slicing—unless you're impatient like me, in which case just grab a fork and go for it.