Step 1

Preheat your oven to 350 degrees F.  Grease an 8-inch or 9-inch round cake pan, or an 8-inch square pan.  I also like to line the bottom of the pan with parchment paper, to give extra insurance that the cake will come out cleanly.  Just trace the bottom of the pan on a sheet of parchment paper and cut it out, then place inside the pan.

Step 2

In a large bowl, whisk together dry ingredients: flour, cocoa powder, sugar, salt, espresso powder, and baking soda. Make sure to whisk vigorously and tamp out any cocoa powder lumps.

Step 3

Pour in the wet ingredients: coffee, olive oil, vanilla, vinegar.  Whisk it all together until a smooth batter is formed.  You'll notice it might get a little foamy - that's the baking soda/vinegar reaction happening.  Stop whisking when the mixture is combined and no lumps remain - don't overmix or the cake will be tough.

Step 4

Pour batter into prepared pan, and bake for 28-32 minutes if using a 9-inch round pan, or 32-34 minutes if using an 8-inch round or square pan, until cake springs back when touched and a tester inserted in the center comes out clean.

Step 5

Let cake cool in pan on a rack for 10 minutes, then invert the pan onto the rack to release the cake, remove the parchment from the bottom, and flip back right side up onto a cake plate.  Let cake cool while you prepare the ganache.

Step 6

In a microwave-safe measuring cup or bowl, heat the heavy cream until bubbling but not boiling, about 30-40 seconds in my microwave.  You can also heat it on the stove.

Step 7

While the cream is heating, place the chopped chocolate in a medium bowl.  Pour the hot cream over the chocolate and let stand for about 30 seconds.  Whisk the mixture until a smooth and glossy ganache forms, about 30 seconds.

Step 8

You can either pour the warm ganache over the cake immediately, or let ganache sit at room temperature for 1-2 hours and then spread it on the cake. It's delicious either way.