Preheat oven to 350 degrees F and grease a 9"x13" baking pan with nonstick cooking spray. Set aside.

In a mixing bowl, combine sugar, flour, cocoa powder, salt and baking soda. Mix well. Set aside. In a smaller bowl, add eggs, oil and vanilla and whisk well. Add wet ingredients to the dry and mix until just combined. Divide chocolate batter in half and spread half of the mixture into the prepared pan. This layer will be thin. Set aside remaining batter.

In a small bowl, combine eggs and pumpkin puree and whisk well, set aside.

In a separate mixing bowl, add sugar, flour, pumpkin pie spice, salt and baking soda and mix well. Add wet ingredients and mix until combined. Spread half of the pumpkin mixture on top of the chocolate layer in the pan.

Using a tablespoon portion scoop, scoop dollops of the remaining chocolate batter in the pan and the remaining dollops of pumpkin batter. Use a knife to swirl the batter.