Heat oven to 350 degrees.
Grease and flour bundt pan, set aside.
In a large bowl, beat softened butter and sugar until creamy.
Add egg and egg whites, mix well.
Add flour, baking powder, baking soda, salt, cinnamon, nutmeg, pumpkin and a 1/2 cup water. Mix on low speed until blended, scraping sides of bowl often. Increase speed to medium for another 2 minutes.
Remove about 3/4 cup of the batter, place in small bowl, set aside.
Spoon remaining batter into bundt pan.
To reserved batter add cocoa powder and 1 tablespoon water. Stir to combine.
Place spoonfuls of chocolate batter on top of pumpkin batter.
Using a knife, swirl chocolate batter into pumpkin batter to marble.
Bake 45 minutes or until toothpick inserted comes out clean.
Cool for 10 minutes in pan, remove from pan to invert onto wire rack and let cool completely