1 1/2cups(340 grams) unsalted butterroom temperature
1 1/2cupsblack coffee
1cup(85 grams) Dutch-process cocoa powder
6ounces(170 grams) finely chopped dark chocolate roughly 72%
2cups(455 grams) light brown sugar, packed
7(350 grams) large eggsroom temperature
2cups(255 grams) all-purpose flour
10ounces(284 grams) semisweet or bittersweet chocolatechopped or chips
1/2cup(100 grams) granulated sugar
1cup(230 grams) heavy cream
2tablespoons(28 grams) unsalted butter
Hazelnut Caramel Crunch
3/4cup(150 grams) granulated sugar
1cup(124 grams) hazelnutstoasted
Whipped Cream Filling
1 1/2cups(345 grams) heavy cream
1cup(232 grams) creme fraiche
1/4cuplight brown sugar
For the Devil’s Food Cake
Adjust oven rack to lower-middle position and preheat to 350°F (180°C). Line three 8- by 2-inch anodized aluminum pans with parchment and grease with pan spray. (The cakes can be baked in 2-inch-deep pans, but they will dome more and rise less.)
Prep all your ingredients by measuring or weighing them into individual bowls. Place the chopped chocolate and cocoa in a medium or large bowl. Measure the brown sugar and salt in another bowl. Place the eggs in a medium bowl and whisk to combine. Place the flour in a medium bowl and the baking soda in a small prep bowl.
Combine butter and coffee in a 4-quart stainless steel pot over low heat. Once melted, remove from heat, then mix in the cocoa and chocolate, followed by the brown sugar, vanilla, and salt. Mix in the eggs, then sift in the flour and add the baking soda. Whisk thoroughly to combine.
Divide batter between prepared cake pans, about 23 ounces each. (If you don't have three pans, the remaining batter can be held at room temperature up to 90 minutes, though the rise will not be quite as high.) Bake until cakes are firm but your finger can still leave an impression in the puffy crust, about 30 minutes (a toothpick inserted into the center should come away with a few crumbs still attached).
Cool cakes directly in their pans for 20 minutes then run a butter knife around the edges to loosen. Invert onto a wire rack, peel off parchment, and return cakes right side up.
For the Caramel Ganache
Put the chocolate into a small heat-resistant bowl and set aside.
Put the sugar and water in a saucepan over medium heat and stir just until the sugar has dissolved. Let the syrup come to a boil without stirring. Cook the syrup until it turns a dark amber color, about 350 degrees F. Swirl the pan to distribute the color and heat.
Once the syrup reaches the desired color, take the pan off the heat and pour in 1/2 cup of the cream. Do this carefully, as the caramel is very hot and will bubble up when you add the cream. Once the bubbling subsides stir in the rest of the cream 1/2 cup of cream, then stir in the butter one tablespoon at a time. Place the pan back over medium heat and stir to combine all the ingredients. Once the ingredients are all incorporated into the caramel, pour it over the chocolate. Swirl the bowl so that the chocolate is completely coated with the warm caramel, then cover and let sit for 5 minutes. With a whisk, stir the mixture slowly, starting with small circles in the middle and working your way outward, whisking a bit more briskly as you go, until you have a smooth, glossy frosting.
Leave the ganache on your kitchen counter until it reaches spreading consistency, about 2-3 hours. If it stiffens up too much, simply place the bowl over a pan over simmering water for a few seconds and stir until the ganache is soft again.
Covered with plastic wrap at room temperature, this frosting keeps for up to 3 days.
For the Hazelnut Caramel Crunch
Line a baking sheet with parchment paper or Silpat. Measure the baking soda into a small bowl and set aside. In a medium saucepan, combine the sugar, water and corn syrup and place over medium high heat. Stir until the sugar is dissolved. Bring to a boil and cook undisturbed until the sugar starts to color around the edges. Gently swirl the pan to even out the color and continue to cook until the mixture turns a light amber. Immediately remove the pan from the heat and stir in the nuts. Stir until the nuts are thoroughly coated. Stir in the baking soda, it will foam. Pour the mixture onto the prepared baking sheet. Do not spread the mixture. Let it cool completely.
Transfer the slab to a cutting board and use a sharp knife to cut into 1/2-inch pieces. Set aside about half of the crunch and the largest pieces for decorating the top of the cake.
For the Whipped Cream Filling
In the bowl of stand mixer, combine the heavy cream, crème fraiche and sugar. With the whisk attachment beat on low speed to combine the ingredients and then increase to medium high speed and whip until soft peaks form.
Assembling the Cake
Level cakes with a serrated knife and set scraps aside for snacking. Place a cake board on a cake turntable. Place 1 layer on a cake board. Spread a thin layer of the whipped cream over the cake layer. Cover the cream with about 1 cup of the caramel crunch. Top the crunch with half of the whipped cream filling spreading it just to the edges. Top with the next layer and repeat with the thin layer of cream, the caramel crunch and the remaining whipped cream. Top with the final cake layer. Lightly scrape the around the edge of the cake with an offset palette knife to even off any whipped cream peeking out.
Crumb coat the cake by spreading a thin layer of chocolate ganache on the sides and tops of the cake. Some of the ganache will mix with the cream, but that is okay. It will be covered by the final coat of ganache. Refrigerate the cake for 20 minutes until firm to the touch.
To glaze the cake, the chocolate should be cool but spreadable. If the ganache is stiff warm the ganache by placing the bowl directly over simmering water for a few seconds and stir constantly. Scrape the ganache onto the center of the cake and working quickly use an offset spatula to spread the ganache over the top and down the sides of the cake.
Refrigerate the cake until about 40 minutes before serving. Decorate the cake with the remaining pieces of caramel crunch. Serve immediately.
If you are using the ganache as a frosting (rather than a glaze), make it at least 2 or 3 hours before you'll need it, as it takes time to reach a spreading consistency.