Cocoa powder is the star ingredient in this recipe, providing the deep chocolate flavor that makes this cake irresistible. Unsweetened cocoa powder is recommended for this cake, as it balances the sweetness of the sugar while contributing to the rich, fudgy texture. The process of "blooming" the cocoa powder by mixing it with warm water enhances its flavor, making the cake even more decadent.

Buttermilk plays a crucial role in baking by adding moisture and tenderness to the cake. Its acidity reacts with baking soda, helping the cake rise and creating a light, fluffy texture. Additionally, buttermilk imparts a subtle tanginess that balances the sweetness, resulting in a more complex flavor profile. Using full-fat buttermilk is recommended for the best results, as it adds richness and a delightful creaminess to the batter.

To make this delectable cake, you will need the following ingredients:

2 cups all-purpose flour
2 cups granulated sugar
½ cup unsweetened cocoa powder
1½ teaspoons baking soda
1 teaspoon baking powder
¼ teaspoon salt
2 large eggs (room temperature)
½ cup melted butter
½ cup canola oil (or any neutral oil)
1 cup buttermilk (room temperature)
1 cup hot water (not boiling)

¾ cup unsalted butter
½ cup unsweetened cocoa powder
⅓ cup buttermilk (room temperature)
1 teaspoon vanilla extract
2½ to 3 cups powdered sugar (sifted)

Preheat the Oven: Preheat your oven to 350°F (177°C). Grease and line a 9x13 inch baking pan with parchment paper for easy removal.

Mix Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, cocoa powder, sugar, baking soda, baking powder, and salt until well combined.

Combine Wet Ingredients: Add the melted butter, oil, eggs, and buttermilk to the dry ingredients. Mix until just combined. Slowly add the hot water and stir until the batter is smooth.

Bake the Cake: Pour the batter into the prepared baking pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Cool the Cake: Allow the cake to cool in the pan for 15-20 minutes before transferring it to a wire rack to cool completely.

Prepare the Frosting: In a saucepan over low heat, melt the butter. Whisk in the cocoa powder and cook for about 1 minute to bloom the cocoa.

Combine Ingredients: Remove from heat and whisk in the buttermilk, powdered sugar, and vanilla extract until smooth.

Frost the Cake: Once the cake is completely cool, pour the frosting over the top and spread evenly. Allow the frosting to set before slicing.

Use Room Temperature Ingredients: Ensure that your eggs and buttermilk are at room temperature for better mixing and a lighter texture.
Don't Overmix: Mix just until combined to avoid incorporating too much air, which can lead to a dense cake.
Check for Doneness Early: Start checking your cake for doneness a few minutes before the recommended baking time to prevent overbaking.

This buttermilk chocolate cake with cocoa powder is a must-try for any chocolate enthusiast. Its rich, moist texture combined with the smooth chocolate frosting makes it an irresistible dessert for any occasion. Whether served at a celebration or enjoyed as an everyday treat, this cake is sure to become a favorite in your baking repertoire. So gather your ingredients, preheat your oven, and indulge in this delightful chocolate creation!