Preparation Steps

• Line two 8-inch round cake pans with parchment circles and lightly grease the sides. Heat the oven to 335°F (170°C). If using cake strips, soak them now and attach before baking.
• Bloom the cocoa: In a heatproof bowl, whisk the cocoa powder and espresso powder into the hot coffee until smooth and glossy. Set aside to cool for 5 minutes.
• In a large mixing bowl, whisk together flour, sugar, baking powder, baking soda, and salt for 30 seconds to evenly distribute the leaveners.
• Add the eggs, sour cream, oil, vanilla, and molasses to the dry ingredients. Mix on low until a thick batter forms. With the mixer running on low, stream in the cocoa-coffee mixture in two additions, scraping the bowl once, until the batter is smooth and pourable.
• Divide batter evenly between the pans. Bake at 335°F for 28–33 minutes, rotating once, until the centers spring back and a toothpick comes out with a few moist crumbs.
• Cool cakes in pans for 15 minutes, then turn out onto wire racks to cool completely. For neater stacking, wrap cooled layers and chill 20–30 minutes (or freeze 10–15 minutes) before frosting. Level domes if needed.
• Make the buttercream: Beat the butter on medium-high speed for 4–5 minutes until very pale and fluffy. Sift together the cocoa and about half of the powdered sugar. Add the cocoa mixture, salt, and espresso powder (if using) to the butter and beat on low until combined, then on medium for 2 minutes. Mix in vanilla and 4 tablespoons cream. Add remaining powdered sugar, then cream 1 tablespoon at a time until smooth and spreadable. Whip 1–2 minutes to aerate.
• Assemble: Smear a little frosting on a cake board. Set down the first cake layer. Spread about 1 1/4 cups frosting over the top, pushing just to the edge. Place the second layer on top and press gently to level. Apply a very thin crumb coat around the sides and top and chill 20 minutes. Add a final, thicker coat and smooth with an offset spatula or scraper; chill 15 minutes until cold to the touch.
• Ganache drip: Warm cream until steaming (do not boil). Pour over the chopped chocolate with corn syrup and a pinch of salt. Let sit 2 minutes, then stir from the center outward until silky. Cool to about 95–100°F; it should flow slowly off a spoon.
• Finish: With the cake well-chilled, use a spoon or squeeze bottle to drip ganache around the edges, then spread a thin layer over the top. Let set 10 minutes and garnish with chocolate curls or shards.