Preheat the oven to 350 degrees F. Grease one 8-inch round cake pan, line with parchment paper, then butter or spray with cooking spray.
In a medium size bowl combine the flour, sugar, unsweetened cocoa powder, baking soda, baking powder and salt. Set aside.
In the bowl of a stand mixer (or use a hand held mixer) beat together the eggs, buttermilk, canola oil and vanilla until smooth. Slowly add the dry ingredients to the wet ingredients with the mixer on low until there are no longer any clumps of flour. Stir in the hot coffee and mix until combined. Batter should be pourable, but not super thin. Stir in the chocolate chips.
Pour the batter evenly into the cake pan. Bake 25 to 30 minutes, until the tops are just set and no longer wiggly in the center. Remove and let cool five minutes, then run a knife around the edges of the pan. Grab 1 large flat plate, line it with wax or parchment paper and invert the cakes onto the paper-lined plates. Cover and let the cakes cool, then freeze 4 hours or overnight until firm.