Preheat your oven to 325°F (163°C). Lightly spray an 8-inch round cake pan with non-stick spray, line the bottom with parchment paper, then spray again. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Mix on low speed until everything is well incorporated.

In a separate bowl, whisk together the buttermilk, hot water or coffee, oil, eggs, and vanilla extract.

With the mixer on low, gradually pour the wet mixture into the dry ingredients, scraping down the sides and bottom of the bowl with a rubber spatula to ensure a smooth batter.

Pour the batter into the prepared cake pan and bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Let the cake cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely—or serve warm topped with ganache.

In a microwave-safe bowl, heat the heavy cream for about one minute, until hot but not boiling. Pour the hot cream over the chocolate chips and stir until smooth and glossy.

Allow the ganache to cool slightly; it will thicken as it cools.