Preheat oven to 350F. Grease an 8×8″ or an 11×7″ baking pan.
Beat together melted butter, sugar, and vanilla, then beat in eggs one at a time. Combine dry ingredients in small bowl, and then gradually stir into butter mixture by hand.In another bowl, beat cream cheese and sugar until smooth. Beat in remainder of ingredients until smooth.
Spread about 2/3 of chocolate batter into prepared pan. Spread the pumpkin batter over top, distributing evenly. Drop the remaining brownie batter over cheesecake batter. To make the swirls, run a butter knife back and forth through the pan.
Bake for 35-40 minutes, or until a toothpick inserted in the center comes out clean.Cool completely and chill before cutting and serving.