Chocolate Buttermilk Cake

Ingredients

• 3 cups granulated sugar (600g)
• 2 1/4 cups all-purpose flour (280g)
• 3/4 cup unsweetened cocoa powder, sifted (75g)
• 2 1/2 tsp baking powder (10g)
• 1 tsp fine salt (6g)
• 1 cup unsalted butter, room temperature (226g)
• 1 cup carton egg whites or 7 large egg whites, room temperature (235g)
• 1 1/2 cups buttermilk, room temperature (360g)
• 2 Tbsp vegetable or canola oil (30g)
• 2 tsp vanilla extract or vanilla bean paste (8g)
• 1 tsp instant espresso - optional
• 2 cups (4 sticks) unsalted butter, room temperature (454g or 1 lb.)
• 1 cup sifted, dark baking cocoa (80g)
• 1 tsp vanilla extract or vanilla bean paste (4g)
• 1/2 tsp fine salt (3g)
• 5 cups powdered sugar (625g)
• 2/3 cup heavy whipping cream, room temperature (180g)
• 1 1/3 cups dark chocolate chips, melted and cooled (230g)

Instructions

1. 1

   --- Chocolate Buttermilk Cake Layers: ---

2. 2

   Preheat oven to 350°F / 175°C. Line four 7", three 8", or two 9" pans with parchment rounds and grease with nonstick spray. Set aside.

3. 3

   Mix 3 cups sugar, 2 1/4 cups all-purpose flour, 3/4 cup of cocoa powder, 2 1/2 tsp baking powder, and 1 tsp salt together in a stand mixer with a stand mixer and paddle attachment or hand mixer until fully combined.

4. 4

   Mix in 1 cup of room temperature, unsalted butter slowly into the dry ingredients on a low speed. Continue to mix until no large chunks of butter remain, and the mixture looks like moist sand.

5. 5

   Pour in 1 cup of egg whites and mix on low until just incorporated. Mix in 1 1/2 cups of buttermilk in two installments, on a low speed.

6. 6

   Add in 2 Tbsp of vegetable oil, 2 tsp of vanilla extract, and 1 tsp instant espresso. Mix on a low speed until fully incorporated.

7. 7

   Scrape down the sides of the bowl with a rubber spatula, then beat on a medium speed for about a minute to make sure everything is properly mixed together. This also helps lighten the texture of the cake layers a bit.

8. 8

   Divide the batter evenly between your prepared pans. I like to use a scale to make sure each pan has the same amount of batter and will bake up to the same height.

9. 9

   Bake for 33-35 minutes or until a toothpick comes out with a few moist crumbs.

10. 10

    Let the pans cool for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate the cake from the pan.

11. 11

    Place the cake layers into the freezer for 30 minutes to accelerate the cooling process. Once the layers are fully cooled, carefully flip the pans and remove the layers.

12. 12

    Use a serrated knife to level the tops of the layers right before you plan to assemble your cake, or you can wrap and freeze them in advance. They can also be wrapped tightly with plastic wrap and stored at room temperature for a few days.

13. 13

    If you make these cake layers in advance and freeze them, let them thaw for about 20 minutes before making your cake. The cake layers should still be slightly cold to the touch, which will make it easier to assemble your cake.

14. 14

    --- Dark Chocolate Buttercream Frosting: ---

15. 15

    Beat 2 cups of butter on a medium speed for 30 seconds with a paddle attachment until smooth.

16. 16

    Add in 1 cup sifted dark cocoa, 1 tsp vanilla extract, and 1/2 tsp salt, and mix on low until the ingredients are fully incorporated.

17. 17

    Slowly mix in 5 cups of powdered sugar. Halfway through, add in 2/3 cup of heavy cream to make the frosting easier to mix. Scrape the sides and bottom of the bowl as needed with a rubber spatula.

18. 18

    Then mix in 1 1/3 cups of melted and cooled dark chocolate on a low speed until the ingredients are fully incorporated and the desired consistency is reached.

19. 19

    To make the frosting extra smooth, stir by hand with a rubber spatula for a couple of minutes. Push the frosting back and forth to work out any extra air that was incorporated while the frosting was being mixed. Cover with plastic wrap to prevent crusting and set aside.

20. 20

    Repeat step 5 and stir the frosting by hand again right before you use it. Sometimes as frosting sits it develops air bubbles. Giving it a good stir helps make sure it stays silky smooth before you add it to your cake or cupcakes.

21. 21

    --- Assembling This Chocolate Buttermilk Layer Cake: ---

22. 22

    Stack and frost cake layers on a greaseproof cake board or flat plate, using a dab of frosting to help stick the first cake layer to the board.

23. 23

    Add an even layer of buttercream between each cake layer with an offset spatula.

24. 24

    Add a thin coat of frosting around the cake, and fully cover the cake layers.

25. 25

    Smooth using a bench scraper, then chill the cake in the fridge (30 minutes) or freezer (10 minutes) until the frosting is firm to the touch.

26. 26

    Add a second, thicker layer of frosting to the cake, and smooth using a bench scraper. Then decorate as desired and enjoy!