Grease a 9x13 pan and dust with flour. Preheat oven to 350 F. Take out three medium sized bowls for mixing.
Prepare brownie mix according to box directions.
In second bowl: beat vanilla, sugar and eggs with a hand mixer until mixed well (1-2 minutes.)
In third bowl: mix flour, salt and baking powder together. Pour into bowl two and beat together until mixed well. Now add pumpkin, oil and cinnamon. Beat until mixed.
Pour half of chocolate mix into the bottom of your 9×13 pan. Next, pour half of pumpkin mixture on top of that. Repeat both.
Swirl with a small spatula or butter knife until you get a marbled look.
Bake for 40-50 minutes or until you can stick a toothpick in and it comes out clean.