Preheat oven to 350 degrees F. Line two 8-inch cake pans with parchment paper and grease lightly. Line 12 muffins tins.
Sift together dry ingredients: flour, cocoa powder, baking powder, baking soda, salt, cinnamon and espresso powder. Set aside.
In a medium bowl, whisk together buttermilk, sour cream, pumpkin puree and vanilla. Set aside.
Using a stand mixer, cream together butter and sugars with a paddle attachment. Add eggs one at a time, making sure to scrape down bowl between eggs.
In three additions, alternate adding dry mixture and wet mixture to butter. Scrape down bowl occasionally to make sure all ingredients are fully incorporated.
Fill muffins tins 2/3 full with batter. Divide remaining batter between the 2-8in round pans. Bake cupcakes for 20-25 minutes, or until toothpick inserted in the center comes out clean. Bake cake rounds for 30-35 minutes, or until toothpick inserted in the center comes out clean. Let cake rest for a couple minutes in pan before unmolding and allowing to cool completely.