INGREDIENTS

12 tbsp softened butter 1¼ cup flour
½ cup almond flour 1¼ tsp baking soda
½ tsp baking powder 1 tsp salt
¾ cup hot water
4 oz unsweetened chocolate
¼ cup cocoa powder

• ¾ cup granulated sugar 4 large eggs
• egg yolks

¾ cup sour cream  2 tsp vanilla extract For the frosting:
16 oz bittersweet chocolate 1 cup sugar
2 tbsp water
2 cups heavy cream 4 tbsp salted butter
 
Jon Premosch / Jenny Chang / Marie Telling / BuzzFeed
PREPARATION
Prepare frosting first to let it settle completely before frosting cakes. In a pan, heat sugar and water over medium heat, stirring constantly until sugar is completely dissolved.
Let mixture bubble, swirling pan occasionally until syrup turns into brown caramel. Take it off the heat and stir in ½ cup heavy cream. Whisk and once bubbling quiets down, add rest of the cream.
Add salted butter, half a tablespoon at a time. Place pan over heat again and stir until well combined. Stir in chocolate and mix until melted. Whisk until mixture is glossy. Let sit at room temperature for 4 hours, until thickened.
Two hours before assembling, preheat oven at 350°F and grease three 8-inch cake pans.
In a heatproof bowl, combine hot water, cocoa powder, and chocolate. Place bowl in a bain-marie and stir until perfectly melted and combined. Add 3/4 cup sugar to the bowl and stir until smooth. Set aside.
 
In a medium bowl, mix the flour, almond flour, baking soda, baking powder, and salt together.
In a large bowl, whisk the eggs and egg yolk. Add the rest of the sugar and whisk until light yellow and creamy. Stir in chocolate and mix until smooth and well combined. Progressively stir in butter, mixing well until perfectly combined.
Stir in a third of the flour mixture and mix with spatula until well-combined. Stir in half of the sour cream and combine well. Stir in a second third of the flour mixture. Combine. Then the other half of the sour cream and the vanilla extract. Pour in remaining flour mixture and whisk until smooth and well-combined.
Fold batter with spatula then pour a third of batter into each of the cake pans. Tap each pan a couple of times against your counter to smooth the dough and spread it evenly.
Bake 25 to 30 minutes until toothpick comes out almost perfectly clean. If your oven is small and you have to place cakes on oven racks at different levels, make sure to rotate the cakes halfway through cooking.
Cool cakes 30 minutes before inverting on wire rack. Let them cool completely before frosting (about an hour).
To assemble, start by leveling your cakes if you want perfectly straight and smooth layers (you can also skip that step for a more rustic, but equally delicious, look). Lie the blade of a serrated knife on the top of your cake, and trim any bumps off the surface.
Place a teaspoon of frosting in the middle of you cake stand and spread it. This will ensure your cake won’t slip during frosting. Place first cake on top of frosting. With icing spatula, spread frosting on top of first cake, until you get a smooth layer of about ¼ inch. Place second cake on top, making sure it’s centered. Spread another layer of frosting on top. Top with third cake. Make sure all the cake sides are lined up, adjust if not.
With icing spatula, apply frosting on the sides of the cake, rotating cake stand as you go along. Apply frosting on top of the cake, too.
Placing blade of bench scraper right against side of the cake, smooth frosting until cake is evenly coated, rotating cake stand as you go along (this is the first layer of coating so it doesn’t have to be perfect.) Chill for an hour, until set.
With icing spatula, apply second layer of frosting all around cake. Smooth with bench scraper until glossy, even, and smooth.