CHOCOLATE BUTTERCREAM FROSTING FOR CAKE RECIPES

Steps:

• For the cake: Preheat the oven to 350 degrees F. Grease and flour two 9-inch cake pans.
• Sift together the flour, baking powder and salt in a large bowl and set aside.
• In an electric mixer, mix the butter and granulated sugar on high speed until fluffy. Scrape the sides of the bowl and mix for a few more seconds. Add the eggs one at a time, mixing well after each addition. Add the vanilla and mix to combine. Alternate adding the dry ingredients and milk in 3 batches, mixing for a few seconds after each addition. Scrape the sides of the bowl, then mix 1 final time.
• Divide the batter between the prepared cake pans and bake until done (a wooden skewer inserted in the cake should come out completely clean), 28 to 30 minutes. Allow to cool for 10 minutes, then turn out to cool completely.
• For the buttercream frosting: Sift the powdered sugar and cocoa together in a large bowl and set aside.
• In an electric mixer with the paddle attachment, cream the butter until smooth, about 2 minutes. Turn off the mixer and add half of the sugar/cocoa mixture. Turn to low speed and mix to combine. Add the rest of the mixture and mix again. Add the cream, vanilla and salt, scrape the sides and beat until fluffy, 2 to 3 minutes. Thin out with a tablespoon of cream at a time if needed.
• Ice the cake with a generous layer in the center and spread all around the sides. WARNING: MUST BE SERVED WITH A GLASS OF COLD MILK!

Steps:

• Preheat the oven to 350 degrees F and grease and flour two 9-inch round cake pans. 
• In a big bowl, mix the flour, sugar, baking soda, and salt. 
• In a medium saucepan over medium heat, melt the butter. Whisk in the coffee, cocoa powder, and 1/2 cup water and heat it for a minute, stirring constantly. Pour the melted butter mixture into the flour mixture and whisk until well combined. 
• In a medium bowl, whisk the eggs, buttermilk, and vanilla. Add it to the batter and mix until smooth. 
• Divide the batter between the two cake pans, scraping all the batter from the bowl with a rubber spatula. Bake for about 40 minutes, or until a toothpick inserted into the center comes out clean. Let cool for 15 minutes in the pans and then turn out onto a wire rack to cool completely. 
• Frost with buttercream frosting
• In the bowl of a stand mixer fitted with the whisk attachment, combine all the ingredients. Whip the mixture on low speed for a while. When the sugar is incorporated, turn the mixer speed up and whip until the buttercream is smooth and looks right to you. If it's too cold, persuade it with a blowtorch if you have one. If it's too wet, add a bit more powdered sugar. If it's too stiff, add a bit more butter. Be sure to scrape the sides of the bowl once or twice to make sure everything is combined. 
• Use immediately or store in an airtight container at room temperature for 24 hours or in the fridge for up to 2 weeks. Rewhip cold buttercream before using it. 
• Variation: The water/coffee combo in this recipe can be switched up, but remember, coffee is to chocolate like salt is to beef. Coffee brings out the flavor of chocolate without making it taste like coffee, just as salt brings out the flavor of meat without making it taste salty. The liquid you use can be all water, or it can be a full cup of coffee for more of a mocha-flavored cake. And if you're feeling really bold, go ahead and use a cup of a dark stout beer instead. Get creative and experiment a little — after all, it is a science project.