Preheat the oven to 350F (I use convection cuz my oven runs really hot at the bottom - conventional is also fine) and grease and line an 8x3 inch or two 8x2 inch baking pans with baking spray and parchment paper (I did one cake pan and sliced them in half).
In a large bowl, whisk together the flour, cocoa powder, baking powder and salt until they’re evenly distributed.
240 grams (2 cups) cake flour, 80 grams (1 cup) black cocoa powder, 1/2 tsp fine sea salt, 14 grams (1 Tbsp) baking powder
In a separate large bowl, whisk the sugar, oil, eggs and sour cream until they’re well combined and smooth.
350 grams (1 3/4 cup) granulated sugar, 160 mL (2/3 cup) canola oil, 2 large eggs, 150 grams (2/3 cup) sour cream
Sift the dry ingredients over the wet and whisk them together, just a little - about halfway or so.
Pour in the hot coffee and whisk until the batter is completely smooth and all the dry ingredients are combined.
240 mL (1 cup) hot coffee
Scrape the edge of the bowl and give it a good mix. Pour into prepared cake tin(s).
Bake for 40ish minutes (if baking in one pan - 20-25 if baking in two separate pans), until the tallest part of the cake, in the center, springs back when you press on it. If you’re hesitant, give it another minute or so.
Let the cake rest for 10 minutes in the pan, then flip over onto a tea towel and let the cake cool upside down for 30 minutes or so before flipping back over.
Once it's cooled, slice the cake in half.
60 mL (2oz/1/4 cup) espresso (cooled)