Step 1

Arrange a rack in the middle of the oven and heat the oven to 350ºF. Coat 2 (9-inch) round cake pans with cooking spray. Dust with all-purpose flour and line the bottom of each with a parchment paper round.

Step 2

Place 3/4 cup natural cocoa powder in a medium bowl, add 1 cup hot brewed coffee, and whisk to combine. Set aside to cool slightly. Meanwhile, place 2 cups all-purpose flour, 2 teaspoons baking soda, 1 teaspoon kosher salt, and 1 teaspoon baking powder in a large bowl and whisk to combine.

Step 3

Place 2 cups granulated sugar, 3/4 cup vegetable oil, and 2 large eggs in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Beat with the paddle attachment on medium speed until lightened in color and smooth, about 1 minute. Add the flour mixture and beat on low speed until just combined.

Step 4

Add 1 cup whole milk and 1 teaspoon vanilla extract to the cocoa mixture and whisk to combine. Transfer half to the cake batter and beat on low speed until smooth, scraping down the sides of the bowl as needed. Add the remaining cocoa mixture and beat on low speed until smooth, scraping down the sides and bottom of the bowl as needed (the batter will be thin), about 1 minute.

Step 5

Divide the batter between the cake pans (generous 2 2/3 cups or 23 ounces each). Bake, rotating the pans halfway through, until the top of the cakes bounces back when gently pressed and a toothpick inserted into the center comes out clean, 35 to 40 minutes total.

Step 6

Place the cake pans on a wire rack and let cool for 15 minutes. Remove the cakes from the pan to the wire rack and discard the parchment paper. Let cool completely, about 1 hour. Meanwhile, make the frosting.

Step 7

Make the roux: Place 1 cup whole milk, 1/4 cup all-purpose flour, and 1 pinch kosher salt in a medium saucepan. While whisking constantly, bring to a simmer over medium heat. Continue to cook until thick and pudding-like, about 4 minutes total cooking time. Add 1 cup granulated sugar and whisk until combined.

Step 8

Remove the saucepan from the heat. Transfer the mixture into a fine-mesh strainer and press it through into a shallow medium bowl or baking dish. Press a sheet of plastic wrap directly onto the surface and let cool to room temperature, about 1 1/2 hours. Meanwhile, place 2 sticks unsalted butter and 1 teaspoon vanilla extract in the bowl of a stand mixer. Let sit at room temperature until the butter is softened.

Step 9

Beat the butter mixture with the paddle attachment on medium-low speed until the butter is soft and lightened in color, 3 to 4 minutes. Reduce the mixer speed to low. Beat in the roux a quarter at a time, mixing well in between additions.

Step 10

Switch to the whisk attachment. Beat on medium-high speed until fluffy and soft, about 4 minutes. If the frosting appears greasy or separated, gently heat it in a double boiler over a pot of simmering water and re-whip. If it appears loose and soft, refrigerate for several minutes before re-whipping.

Step 11

Spread 1 tablespoon of the frosting in the center of a cake or serving plate. Top with 1 cake layer. Spread the remaining frosting over the top of the cake in an even layer, going all the way to the edges. Top with the second cake layer. Refrigerate until the frosting is set, 35 to 40 minutes.

Step 12

Coarsely chop 8 ounces dark chocolate or measure out 1 1/3 cups bittersweet chocolate chips. Place in a medium heatproof bowl and add 2 tablespoons light corn syrup and 1 pinch kosher salt.

Step 13

Heat 1 cup heavy cream in a small saucepan over medium heat until just simmering. Pour over the chocolate and let it sit for 1 minute to begin melting the chocolate. Stir together with a flexible spatula until shiny and smooth. Let cool slightly until it begins to thicken, about 3 minutes.

Step 14

While the ganache sits, place five 3-inch-wide, 5-inch-long strips of parchment paper around the bottom edge of the cake, nestling them just underneath the bottom layer, so that the cake plate is covered and will remain clean when the ganache is poured over top.

Step 15

Pour one third of the ganache (about 2/3 cup) over top of the cooled cake. Use an offset spatula or butter knife to spread it to the edges of the cake so that it runs down the sides, then spread the ganache over the sides of the cake. Repeat twice more with the remaining ganache so that the cake is fully covered. Gently drag the tip of the offset spatula or butter knife across the top of the cake back and forth to create a wavy pattern to mimic the top of a Ding Dong.

Step 16

Carefully remove the strips of parchment from around the base of the cake. Refrigerate until the ganache is set, about 30 minutes.