Preheat your oven to 375 degrees F. Lightly coat the inside of two 9-inch cake pans with baking spray. Place a circle of parchment paper in the bottom of each pan. Coat the top of the paper with more baking spray. Set aside.
In a large mixing bowl, stir together the flour, baking powder, salt, and baking soda. Set aside.
In a medium mixing bowl, whisk together the sugar, brown sugar, oil, eggs, buttermilk, and vanilla until smooth. Whisk in the melted German chocolate until combined and smooth.
Pour the wet ingredients into the dry ingredients and whisk together until there are no lumps. Pour in the boiling water and whisk to combine.
Divide the cake batter evenly between the two prepared cake pans. Bake for 23-28 minutes until a toothpick inserted into the center comes out clean.
Remove the cakes from the oven and let them cool completely in the pan on a wire rack.
Pecan Coconut Frosting
While the cakes are cooling, make the pecan coconut frosting. Add the brown sugar, sugar, butter, egg yolks, and evaporated milk into a medium saucepan. Whisk until combined, there will be chunks of butter, that’s okay.
Place the saucepan over medium heat and cook, whisking constantly until it comes to a low boil. Continue to whisk until everything starts to thicken, about 1 minute.
Take the saucepan off the heat and whisk in the vanilla, toasted coconut, and toasted pecan until combined. Allow the mixture to cool to room temperature in the saucepan.
Chocolate Buttercream Frosting
Once the cakes and pecan coconut frosting are cooled, make the chocolate buttercream. In a large mixing bowl with a hand mixer (or in a stand mixer with the paddle attachment), beat the butter and the cooled semi-sweet chocolate together until smooth. Add the powdered sugar in a little at a time until completely mixed in.
Add the vanilla and 2 tablespoons of milk, and beat to combine. Place the mixer on to medium-high speed and whip for 3 minutes until the frosting is light and fluffy. If the frosting is too thick, add the extra 1 tablespoon of milk.
Assembly
Take the cooled cakes out of the pan. (If the tops are uneven, trim the cake so it's flat on top.) Place one of the cakes bottom-side down onto a serving plate or cake stand.
Frost the top of the first layer with a thin layer of chocolate buttercream. Add half of the coconut pecan frosting on top and smooth it out almost to the edge, leaving a ½-inch border all the way around.
Add the second cake round, top-side facing down, over the frosting. (This gives your cake a flat top.) Add a thin layer of chocolate frosting on top and around the sides of the cake. Add the remaining coconut pecan frosting on top of the cake, leaving a ½-inch border around the edge.
Pipe the remaining chocolate frosting around the top edge of the cake – I used a 1M star tip. Garnish with pecans halves if desired. Cut into 12 slices and serve.(I find that this cake tastes best at room temperature and slices best when chilled. So I recommend chilling the cake, slicing it, and then leaving it out to come up to room temp.)
Notes
If you don’t have buttermilk on hand, you can substitute sour milk instead. Milk together 1 cup or 2% or whole milk with 1 tablespoon of lemon juice or white vinegar. Stir together and let sit for 5 minutes before using.
To toast the pecans: Preheat the oven to 350 degrees F. Place the pecans in a single layer on a baking sheet and pop that into the oven. Bake, for 5-8 minutes, turning every 2 minutes until aromatic. Take the nuts out of the oven and immediately place them onto a plate. They will continue to toast until they become room temperature.
To toast the coconut: Preheat the oven to 350 degrees F. Place the coconut flakes in a single layer on a baking sheet and pop that into the oven. Bake, for 5-8 minutes, turning every 2 minutes until aromatic. Take the nuts out of the oven and immediately place them onto a plate. They will continue to toast until they become room temperature. **I always pull my coconut a shade or two before what I want because it will get a little more brown as it cools.
The chocolate buttercream is completely optional but adds a fun touch to the cake. If you don’t want to make the frosting, I suggest 1.5x the recipe for the coconut pecan frosting. Still, add ½ of the coconut pecan frosting between the layers and then the other ½ on top. It will end up being more of a “naked” cake.
This cake will keep for 2 days at room temperature or up to 1 week covered in the fridge. You can freeze this cake (or slices) for up to 3 months.