Preheat the oven to 350°F. Grease and flour a 9-inch cake pan and set it aside.
In a medium bowl or using a stand mixer, beat together the softened butter, granulated sugar, brown sugar, and vegetable oil until well combined.
Add vanilla and eggs to the mixture and beat until fully incorporated (about 20 seconds).
Combine flour, cocoa powder, baking soda, baking powder, salt, and buttermilk. Mix on low speed until just combined.
Add hot coffee and mix on medium-low speed until fully incorporated.
Pour the batter into the prepared cake pan and bake for 30 minutes or until the cake is done (the sides will pull away from the pan, and the center will spring back when tapped).
Allow the cake to cool for 15 minutes before transferring it onto a cookie sheet. Let it cool completely before frosting.