Dark Chocolate Cake with Roasted Chestnut Buttercream
Prep Time: 30mins
Cook Time: 50mins
Total Time: 1hr20mins
This Chocolate Cake with Chestnut Buttercream has a soft and moist crumb, and a creamy buttercream made with pureed chestnuts. It's a unique and delicious dessert!
For the chocolate cake:
1cupunsweetened cocoa powder
2.75cupsall purpose flour
4extra large eggslightly whisked
1cupmini chocolate chips
For the chestnut buttercream:
8egg yolkswarmed (before separating the egg yolks and whites, place the eggs in a bowl of hot water for 5 minutes)
1.5cupsbutterdiced into small cubes
For the cake: Preheat your oven to 350 degrees F. Butter and flour your cake pans (I like to rub the leftover butter wrappers in the cake pan for easy and resourceful application. You wouldn’t want to waste any of that butter, would you?)
In a big bowl, pour the boiling water over the cocoa powder, and whisk until smooth (it’s essentially a big bowl of unsweetened hot chocolate. Don’t drink it though…it’s pretty bitter).
Place your hot cocoa into an ice bath so it can cool. Next, sift together the flour, baking soda, baking powder, and salt, and set it aside for later.
Place the butter in a stand mixer fitted with the paddle attachment, mix on low for 1 minute, then with the mixer turned up to medium, slowly add in the sugar. Slowly pour in the eggs with the mixer on low, add the vanilla, and continue mixing until absorbed.
Add one third of the dry ingredients and cooled hot chocolate liquid at a time, alternating between the two, starting with the dry and finishing with the hot chocolate liquid. Stir in your mini chocolate chips at the end.
Pour the batter evenly into the prepared cake pans and bake for 25 minutes, until a toothpick inserted into the center comes out clean. Remove from the oven and let the cakes cool.
For the chestnut buttercream: Preheat your oven to 425 degrees F. If your chestnuts are dirty, wipe them off with a damp paper towel. Get a sharp knife, and cut X’s into the chestnuts. If you don’t cut X’s into the chestnuts, they can explode (even after they have cooled), so it’s important to let the steam escape. Plus, it will make the peeling a lot easier! Roast the chestnuts in the oven for about 20-25 minutes on a sheet pan.
Peel both the shell and inner skin off the chestnuts, and open them up so you can see into the middle of the chestnut (it is very common for a few of them to be spoiled in the middle). Discard the spoiled ones. Place your chestnuts in a food processor, add the vanilla, and grind them up as finely as you can. You won’t be able to grind them into a paste with the food processor, but you should be able to turn it into a powder. Set the ground chestnuts aside for later.
In a stand mixer fitted with the whisk attachment, beat the egg yolks on high speed for 8 minutes until they are very pale. In the meantime, combine the sugar and water in a heavy bottomed saucepan over medium heat, and let the sugar syrup simmer toward the soft ball stage (238 degrees on an instant read thermometer). When both the egg yolks and the sugar syrup are ready, pour the sugar syrup into the mixing bowl (the mixer should still be on high speed), aiming as best as you can to pour between the wire whisk and the side of the bowl. Notice that the mixing bowl is very hot to the touch. Beat the egg yolk sugar mixture until the bowl feels neither hot nor cold (it took me about 5 minutes).
Turn the mixer down to medium and add the butter, a couple cubes at a time, to the bowl. Wait until each installment of butter is absorbed until you add the next batch. You want to beat the buttercream for 10 minutes, so it can get nice and fluffy. Fold the chestnut mixture in, spread your buttercream onto the cooled cakes, and enjoy!