Extra Chocolatey German Chocolate Cake

Directions

1. Heat the oven to 350°F. Grease three 8-inch cake pans with nonstick cooking spray or softened butter and line each with parchment paper.
2. To make the cake layers, add the flour, brown sugar, granulated sugar, baking powder, baking soda and salt to the bowl of a stand mixer fitted with the paddle attachment. Beat on low speed until combined.
3. In a small bowl or a two-cup glass measuring cup (my preference), whisk together the oil, buttermilk, eggs, egg yolk, and vanilla. With the mixer on medium-low speed, slowly pour the wet ingredients into the dry ingredients. Beat just until incorporated, scraping down the bowl with a flexible spatula as needed.
4. In the same small bowl or measuring cup (no need to clean it), whisk together the cocoa powder, espresso powder, if using, chopped chocolate and boiling water until the chocolate melts and the mixture is smooth.
5. Pour into the stand mixer bowl and on medium-low speed beat until smooth, about 30 seconds. The batter will be very thin.
6. Transfer the batter to the prepared pans and bake for 22 to 25 minutes, rotating at the halfway point. The cakes are ready when a cake-tester inserted in the middle comes out with a moist crumb or two. Let rest for about 10 minutes, then run a butter knife around the perimeter of each cake layer and invert on to a cooling rack. Let cool to room temp or freeze before filling and frosting. (Once frozen, the layers are sturdier, which is helpful when assembling.)
7. While the cake bakes, make the filling: Warm the butter, brown sugar, salt, egg yolks, and evaporated milk in a medium saucepan over medium to medium-high heat, until the mixture begins to boil, whisking continuously, about 5 to 10 minutes.
8. Once gently boiling, reduce the heat a bit to protect yourself from bursting bubbles, and continue whisking until the mixture thickens, about 5 minutes. Remove from the heat and add the coconut, pecans and vanilla and stir to combine with a flexible spatula. Let cool to room temperature, stirring periodically.
9. While the filling cools, make the frosting: Beat the butter in the bowl of a stand mixer fitted with the paddle attachment on medium-low speed until soft and smooth.
10. In a large bowl, whisk the sugar, cocoa powder, and salt together. Pour the vanilla into the heavy cream.
11. While beating on low, add the sugar–cocoa powder mixture to the stand mixer bowl, one cup at a time, alternating with a tablespoon or so of the cream-vanilla mixture. Once incorporated, beat for 5 minutes until smooth, fluffy and spreadable.
12. To assemble the cake, top one of the layers with 1/3 of the coconut-pecan filling, spreading it gently just to the edges. Top with another layer and repeat. Place the final layer on top, pressing down gently. Frost the top and sides of the cake with only a very thin layer of the chocolate frosting (for that “naked” look) and top the frosted cake with the final third of filling. If using, sprinkle a little flaky sea salt over the top.
13. Refrigerate for 30 to 60 minutes before serving. If your layers were frozen, let the cake come to room temp before serving. The cake will keep on the counter for up to 3 days, lightly covered in plastic wrap.