Preheat oven to 350°F. Grease and flour a 13x9-inch pan. Set aside.

Measure out 1/4 cup of the cake mix. Set aside.

In a large bowl, combine the remaining cake mix, pudding mix, 2 whole eggs, egg yolk, and milk with an electric mixer until combined. Mixture may still be slightly lumpy; that is ok. Gently stir in the cinnamon chips. Pour into the prepared pan and set aside.

In a medium bowl, add the pumpkin puree, reserved 1/4 cup of cake mix, egg white, brown sugar, cinnamon, and nutmeg. Mix with the electric mixer until combined. Dollop the pumpkin mixture on top of the cake batter, then use a knife to swirl it through the batter, leaving large streaks of pumpkin throughout the batter.

Bake for 40-45 minutes, until a toothpick inserted into the center of the cake (in one of the cakey parts, not the pumpkin swirls) comes out clean. Allow to cool, then cut into pieces and serve. Dust with powdered sugar to serve with sweetened whipped cream, if desired.