Preheat oven to 350°F. Prepare two 8x8 inch baking pans with butter and flour or non-stick spray.

In a medium bowl, sift together flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

In a small bowl, combine buttermilk and pumpkin puree. Whisk until smooth.

In a mixer, beat butter, sugars, and vanilla until light and fluffy. Add eggs one at a time, fully incorporating each.

Alternately add flour mixture and buttermilk mixture to the sugar mixture, beginning and ending with flour. Mix until just combined.

Divide batter evenly into the prepared pans. Bake for 18-26 minutes, until a toothpick inserted comes out clean.

While cakes bake, prepare whipped cream by whipping heavy cream until soft peaks form. Fold in pumpkin puree, cinnamon, all-spice, and confectioners' sugar to taste.

For ganache, bring heavy cream to a boil. Pour over chocolate chips in a heat-safe bowl and stir until smooth.