Decadent Dutch Chocolate Buttermilk Cake

1. Prepare Oven and Pans

Preheat your oven to 350°F (175°C) and adjust the oven rack to the middle position. Grease two 9-inch cake pans, line them with parchment paper, and then grease and flour the parchment paper.

2. Melt Chocolate

In a medium heatproof bowl, combine the chopped unsweetened chocolate and Dutch-processed cocoa powder. Pour in the hot water and stir until the chocolate is completely melted and the mixture is smooth and glossy.

3. Combine Dry Ingredients

In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. In a small bowl, combine the buttermilk and vanilla extract.

4. Beat Eggs and Sugar

In the bowl of a stand mixer fitted with the whisk attachment, whip the eggs, egg yolks, and 1.25 cups of sugar on high speed until the mixture is light and fluffy, about 2 to 3 minutes.

5. Add Chocolate and Butter

Switch to the paddle attachment and mix in the cooled chocolate mixture until fully incorporated. Gradually add the softened butter, one piece at a time, beating for about 10 seconds after each addition.

6. Mix Dry and Wet Ingredients

With the mixer on low speed, add the dry flour mixture in three additions, alternating with the buttermilk mixture in two additions, beginning and ending with the flour mixture. Mix each addition for about 15 seconds, ensuring everything is well combined.

7. Final Mix and Divide Batter

Give the batter one final mix with a rubber spatula to ensure no pockets of flour remain. Divide the batter evenly between the prepared cake pans and smooth the tops with the spatula.

8. Bake Cakes

Bake the cakes in your preheated oven for 25 to 30 minutes, or until a toothpick inserted into the center of each cake comes out with a few crumbs attached.

9. Cool Cakes

Allow the cakes to cool in their pans on a wire rack for about 10 minutes. Then, remove them from the pans and let them cool completely on the wire rack.