Preheat the oven to 325F (I use convection cuz my oven runs really hot at the bottom - conventional is also fine) and line 12 muffin tins.
In a large bowl, whisk together the flour, cocoa powder, baking powder and salt until they’re evenly distributed.
120 grams (1 cup) cake flour, 40 grams (1/2 cup) black cocoa powder, 1/4 tsp fine sea salt, 7 grams (1/2 Tbsp) baking powder
In a separate large bowl, whisk the sugar, oil, eggs and sour cream until they’re well combined and smooth.
175 grams (3/4 cup + 2 Tbsp) granulated sugar, 80 mL (1/3 cup) canola oil, 1 large eggs, 75 grams (1/3 cup) sour cream or greek yogurt
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.
120 mL (1/2 cups) hot coffee
Scrape the edge of the bowl and give it a good mix. Fill each cupcake tin about 2/3-3/4 - I measure up to 50 grams.
Dip each chunk of lady finger into the espresso and press it into each cupcake.
4 lady fingers, cut into thirds, 120 mL (1/2 cup/4 oz) espresso
Bake for 16-19 minutes, until the cupcake no longer looks wet and the tallest part, in the center, springs back when you press on it. If you’re hesitant, give it another minute or so.
Let the cupcakes rest for 10 minutes in the pan, then remove them and allow them to cool completely before frosting.
Once they've cooled, use a fork to poke holes all over the tops of the cupcakes. Drizzle or use a pastry brush to soak the cupcakes in the rest of the espresso.