Preheat the oven to 350 degrees Fahrenheit. Spray a 9x5 in loaf pan with no stick baking spray.
Grab two bowls, one large and one medium. In the large bowl mix together the granulated sugar, brown sugar, canned pumpkin, vegetable oil, eggs, vanilla extract and sour cream.
In the medium size bowl, sift together the all-purpose flour, pumpkin pie spice, cinnamon, baking soda and salt. Mix until combined.
Pour the dry ingredients into the wet and mix until completely combined.
Next, pour half of the batter into the empty bowl. Add in the ¼ cup cocoa powder to one bowl of batter and mix.
Alternating pour the pumpkin and chocolate pumpkin batter into the prepared loaf pan. Using a knife, swirl together the batter.
Bake for 45-50 minutes or until a toothpick comes out clean.
Now, let’s make the ganache. In a bowl warm heavy cream until it’s hot but not boiling. Add in chocolate chunks and allow to sit for 2-3 minutes then mix until smooth. Allow to cool then pour over cooled loaf cake.