Ingredients
Equipment
Method
- Step 1: Preheat oven to 350°F (175°C) with the rack in the middle position, line a 9x13 inch (23x33cm) light-colored aluminum pan with parchment paper leaving a 1-inch overhang on both long sides, then lightly grease the parchment and exposed short sides — the parchment overhang is essential for lifting the cooled cake out of the pan cleanly before splitting into two layers.
- Step 2: In a large mixing bowl whisk together the flour, plain white granulated cane sugar, Dutch-process cocoa powder, baking soda, baking powder, and fine sea salt for a full 60 seconds until uniformly dark with no cocoa clumps and no pale flour streaks visible anywhere in the mixture including at the bottom of the bowl.
- Step 3: Add the room-temperature eggs, room-temperature whole milk, neutral oil, and pure vanilla extract into the center of the dry ingredients and whisk from the center outward for approximately 30 strokes until just combined — the batter will still look slightly lumpy and uneven, which is correct, and overmixing at this stage produces a tight crumb that is difficult to split cleanly into two even layers.
- Step 4: Pour the hot strong brewed coffee in a slow steady stream around the edge of the bowl while whisking gently until fully incorporated — the batter will thin noticeably and deepen to a near-black color as the Dutch-process cocoa blooms, and the finished batter should look glossy, very dark, and pourable like a thick pancake batter.
- Step 5: Pour the batter into the prepared pan, spread to the corners with an offset spatula, and bake at 350°F (175°C) for 32–35 minutes until a toothpick inserted in the center comes out with moist crumbs — not wet batter and not completely clean — then leave the cake in the pan on a wire rack for exactly 10 minutes before using the parchment overhang to lift it out, and cool completely at room temperature for at least 1 hour followed by 30 minutes in the refrigerator before splitting — this cooling sequence is for the pre-split stage only and is separate from the post-assembly storage rules.
- Step 6: Place the fully cold cake on a stable flat surface, score a shallow guide groove around the entire perimeter at the halfway point with a serrated knife, then use slow horizontal sawing strokes with no downward pressure to split the cake into two even layers, lift the top layer off carefully using both hands or a wide offset spatula slid underneath for support, and place it cut-side up on a piece of parchment nearby.
- Step 7: Using the handle of a wooden spoon, poke holes across the entire surface of the bottom cake layer spaced approximately 1 inch (2.5cm) apart and pushed down to about ¾ of the depth of the layer — approximately 20–25 holes total — to create anchor points that grip the filling and prevent it from shifting when the top layer is placed.
- Step 8: Whisk the instant vanilla pudding mix and 1 cup (240ml) cold whole milk together for 2 full minutes until thick and spoonable — not pourable — then add the cold heavy whipping cream and whisk 30 seconds to a spreadable consistency, fold in the crushed Oreo fine crumbs and coarse pieces, then spread the filling in an even ¾-inch (2cm) layer across the entire surface of the bottom cake layer pressing gently into the poked holes with an offset spatula until the surface is fully covered with no bare patches.
- Step 9: Carefully lower the top cake layer cut-side down straight onto the filling without sliding it, press very gently across the surface to seat it level, and refrigerate the assembled cake uncovered for a minimum of 2 hours or overnight until the filling is completely set and cold before applying the topping.
- Step 10: Combine the cold heavy whipping cream, sifted powdered sugar, pure vanilla extract, and cornstarch in a cold bowl and whip with a hand mixer or stand mixer on medium then high speed for 2–3 minutes until stiff peaks form — stop immediately at stiff peaks, do not over-whip.
- Step 11: Spread the stabilized whipped cream in a generous even layer approximately ¾ inch (2cm) thick across the entire chilled assembled cake, drizzle the warmed chocolate fudge sauce in a free-form pattern over the cream, press whole Oreo cookies firmly into the cream at evenly spaced intervals, scatter the crushed Oreo crumbs across the surface, refrigerate for at least 30 minutes to firm the topping, then slice with a hot-water-warmed knife wiped clean between every cut — 3 columns by 4 rows yields exactly 12 slices at approximately 3x3 inches (7.5x7.5cm) each, approximately 175–180g per slice.
Notes
Dutch-process cocoa only — not natural cocoa. Natural cocoa changes the leavening balance and produces a flat dense cake that will not split cleanly.
Natural cocoa substitute only if necessary: reduce baking soda to 1 tsp and add 1 tsp white vinegar to the milk.
Cold cake before splitting is mandatory — room temperature 1 hour then refrigerator 30 minutes. Warm cake crumbles under the knife.
Filling: use exactly 1 cup (240ml) milk only. More milk makes the filling too thin to hold between layers.
Crush Oreos in two stages — half fine crumbs, half coarse pieces — for flavor and texture contrast in the filling layer.
Box mix option: 15.25 oz devil's food mix, substitute hot coffee for water. Do not use pudding-in-the-mix varieties.
Make-ahead: assemble completely through the whipped cream topping and refrigerate up to 24 hours before serving — overnight is better than same-day.
Freeze baked and filled cake only — before whipped cream topping. Wrap tightly up to 6 weeks. Apply fresh topping after thawing overnight in fridge.
To halve: use 8x8 inch pan. Reduce baking soda to ¾ tsp and baking powder to ½ tsp. Leavening does not scale linearly.
High altitude: reduce baking soda to 1½ tsp and baking powder to ¾ tsp. Add 2 tbsp flour, reduce sugar 2 tbsp, increase coffee 2 tbsp.
High altitude continued: start checking cake at 28 minutes. Refrigerate fully cooled cake 30 minutes before splitting — high-altitude crumb is more fragile.
Contains: gluten, dairy, eggs, soy (Oreos). Check Oreo packaging for your region's allergen information.