Brooklyn Blackout Cake

Ingredients

• ¼ cup (57g) plus 1¾ cups (398g) whole milk
• 2½ Tbsp. cornstarch
• ½ cup (99g) sugar
• 2 oz. (56g; about ⅓ cup) dark chocolate, chopped
• 3 Tbsp. dark Dutch-process cocoa powder
• 1 tsp. vanilla extract
• ¾ tsp. sea salt
• 1½ cups (340g) Brooklyn Brewery Black Chocolate Stout, or other stout of choice
• 1½ cups (340g) unsalted butter, cut into ½-inch pieces
• 1½ cups (126g) dark Dutch-process cocoa powder
• 3 cups (360g) all-purpose flour
• 2¾ cups (544g) sugar
• ¾ Tbsp. baking soda
• 1½ tsp. salt
• 1 cup (227g) sour cream
• 3 large eggs, at room temperature
• 16 Tbsp. (1 cup, 8 oz.) cold unsalted butter
• 7 cups (795g) confectioners’ sugar, plus more for thickening
• ¾ cup Salted Dark Chocolate Pudding
• ½ cup (42g) dark Dutch-process cocoa powder
• ¼ tsp. salt

Steps

Make the Salted Dark Chocolate Pudding

1. In a small bowl, whisk the ¼ cup whole milk with the cornstarch until smooth and set aside.
2. In a medium saucepan, combine the remaining 1¾ cups milk, sugar, dark chocolate, dark Dutch-process cocoa, vanilla and sea salt. Whisk over medium-low heat until the chocolate melts.
3. Fully incorporate the cornstarch mixture into the chocolate mixture by whisking.
4. Reduce to low heat and stir briskly with a wooden spoon or heatproof spatula. It will simmer and gradually thicken.
5. Cook another 1 to 2 minutes, or until the pudding coats the spoon back and drips off slowly. It will be thick and just starting to bubble. Take off the heat, pour into 4 serving ramekins or bowls and cool.
6. Cover with plastic wrap and refrigerate until set, then serve.

Make the Dark Chocolate Pudding Buttercream

1. Cut the cold butter into ½-inch pieces and let it reach room temperature.
2. In a paddle-fitted stand mixer bowl, mix the butter, 3 cups confectioners' sugar, ½ cup dark Dutch-process cocoa, ¼ teaspoon salt and ¾ cup Salted Dark Chocolate Pudding on low until just incorporated. Beat on medium-high for about 1 minute until creamy and incorporated, then scrape the bowl sides with a rubber spatula.
3. Add more confectioners' sugar in 1 cup additions, mixing on low until thick but spreadable. Beat for 1 minute after each addition; all the remaining sugar may not be needed. Once the desired consistency is reached, scrape the sides.
4. Beat on medium-high for 3 to 4 minutes or until very light and fluffy. It should be thick but spreadable. If too thick, add more cream 1 tablespoon at a time; if too thin, add more confectioners' sugar 1 heaping tablespoon at a time.

Make the Black Chocolate Stout Cake

1. Set the oven to preheat at 350ºF. Grease two 9-inch cake pans with butter, dust them with flour and line them with rounds of parchment. Grease the parchment rounds too.
2. In a large heavy saucepan over medium heat, bring stout and unsalted butter to a simmer. Alternatively, melt the butter in the oven or in a large microwave-safe bowl in a microwave, then whisk in the beer. Take the stout-butter mixture off the heat, whisk in Dutch-process cocoa until smooth and cool for 5 minutes.
3. Meanwhile, whisk the flour, sugar, baking soda and salt in a large bowl.
4. Use a separate large bowl to whisk the sour cream with the eggs.
5. Whisk the stout-butter mixture into the egg mixture. Add the flour mixture and combine with a rubber spatula until fully incorporated and smooth with no lumps, scraping the bowl bottom to include dry flour bits.
6. Divide equally between the prepared pans. Bake for 35 to 40 minutes or until a toothpick in each layer's center comes out clean, then put on a rack to cool.

Finish the Brooklyn Blackout Cake

1. Apply the Dark Chocolate Pudding Buttercream as frosting on the cake.