Pumpkin Swirl Brownies

This recipe is loosely based on a classic by Martha Stewart, with quite a few adaptations and one big change to make this version very easy!
While I nearly always prefer from-scratch recipes, I am not sure that Ghirardelli's Dark Chocolate Brownie Mix can be beat for rich, chocolately, delicious brownies. So, instead of making the chocolate part of these from scratch, that's what I used instead.
The only thing I'd change about these next time would be to add mini-chocolate chips to the pumpkin batter (this was Scott's request, and I think it's a good idea).
Otherwise, these turned out well and I'll probably make them again before fall is over.
Pumpkin Chocolate Swirl Brownies
Makes about 24 brownies

Ingredients

1 box Ghirardelli Dark Chocolate Brownie mix, made according to directions (high-altitude, if applicable)

For the pumpkin batter (make usual altitude corrections if needed, i.e., 1-2 Tbsp more flour, a bit less baking powder):
1 cup flour
1/2 tsp baking powder1/2 tsp salt
3/4 cup white granulated sugar
1 tsp vanilla
2 eggs
3/4 cup canned pumpkin purée
1/4 cup unsalted butter, melted
1 tsp ground cinnamon
1/4 tsp freshly ground nutmeg
1/4 tsp ground cloves
(optional: chocolate chips)
Method:

1. Preheat oven to 325˚F. Spray a 9″ x 11″ baking pan with nonstick cooking spray.

2. Prepare brownie mix according to directions; set aside.

3. In a medium bowl, mix the dry ingredients for the pumpkin batter (flour, baking powder and salt)

4. Beat together the 2 eggs and 3/4 cup of sugar. Mix them for 3-5 minutes until fluffy. Add the vanilla and pumpkin and mix thoroughly. Add the melted butter and spices and blend well. (If desired, add some chocolate chips here!)

5. Pour the dry pumpkin batter ingredients into the wet and use the stand up mixer to combine thoroughly, again without overmixing.

6. Pour 2/3 of the brownie batter into the prepared pan. Spread pumpkin batter on top of the chocolate (this will require being gentle and patient to try and get the batter to stretch evenly across the brownie mix). Using a ziploc bag with a hole cut in the corner, or else working carefully with a spoon and your hand, spread the remaining brownie batter into 3 lines parallel to the long-side of the brown pan. Using a knife, swirl the pattern by slicing through the batter in alternating directions parallel to the short side of the pan.

7. Bake for 30-35 minutes. Allow to cool in the pan.