1. Preheat oven to 350°F. Grease and lightly flour the Bundt pan.
2. In a medium bowl, combine flour, baking soda, baking powder, salt, pumpkin pie spice, and cinnamon. Whisk and set aside
3. In the bowl of a stand mixer with the paddle attachment, cream the butter and sugar until fluffy. Add the eggs one at a time, scraping down the sides of the bowl. Add the pumpkin purée, sour cream and vanilla until combined.
4. Slowly add the dry ingredients and beat until combined. Batter will be thick.

For the Chocolate Swirl:

1. In a separate bowl, mix 1½ cups of the pumpkin batter with the chocolate swirl ingredients and stir until combined.
2. Spread half of the pumpkin batter into the prepared Bundt pan. Spread all the chocolate batter evenly on top. Spread the remaining pumpkin batter and make swirls with a knife or skewer.
3. Bake for 45 to 55 minutes or until a toothpick inserted into the center comes out clean.
4. Remove from the oven and allow to cool for 30 minutes inside the pan. Invert the pan onto a cooling rack to cool completely.

For the Chocolate Ganache:

1. While the cake cools, heat the heavy cream in a small saucepan over medium heat until it starts to foam/boil around the edges. Remove from heat and pour over the chocolate chips. Let it sit for a few minutes and whisk until the chocolate is completely melted. For a thicker ganache add more chocolate chips. Let ganache cool.
2. Spoon the ganache over the cake on the cooling rack. Allow the ganache to set before slicing.