Double Layer Chocolate Cake and Chocolate Buttercream Frosting

I love making people happy with food! This cake is my favorite from the cake to the frosting. 

Prep Time: 30 minutes

Cook Time: 30 minutes

Yield: 12 servings

Ingredients

• 1 1/2 cups granulated sugar 
• 1/2 cup packed light-brown sugar
• 3/4 cup unsweetened cocoa powder
• 1 tsp baking soda
• 3/4 tsp salt
• 1 cup boiling water
• 3/4 cup canola oil
• 2 large eggs
• 3 large egg yolks
• 1 Tbsp vanilla extract
• 2 cups all-purpose flour
• 1/3 cup milk
• 1/3 cup sour cream
Chocolate Buttercream Frosting
• 1 1/2 cups butter, at room temperature (I like to use 1 cup unsalted and 1/2 cup salted)
• 3 3/4 cups + 2 Tbsp powdered sugar
• 1/2 cup + 2 Tbsp cocoa powder
• 3 - 4 Tbsp heavy cream
• 1 tsp vanilla extract

Directions

• For the cake:
• Preheat oven to 350 degrees. Butter two 9-inch round cake pans then line bottom of each with a round of parchment paper. Butter parchment paper and set aside.
• In a large, heat proof mixing bowl, whisk together granulated sugar and brown sugar (lumps are fine), then whisk in cocoa powder, baking soda and salt. Carefully pour boiling water in to cocoa mixture and immediately whisk to blend well, about 15 - 20 seconds. Allow to cool 5 minutes.
• Using an electric hand mixer set on low speed blend in canola oil until combined, about 10 seconds. Add eggs to cocoa mixture and blend on low speed just until combined, about 5 seconds. Add egg yolks and vanilla extract and blend just to combined. Then add flour and blend only until combined and finish by blending in milk and sour cream just until combined.
• Divide mixture evenly among 2 prepared pans. Bake in preheated oven until toothpick inserted into center of cake comes out clean or with a few moist crumbs, about 29 - 34 minutes. Allow to cool in pan 5 minutes, run butter knife around edge of cake and invert onto a wire rack and allow to cool completely (after about 20 minutes of cooling, I placed the cakes into an airtight container to seal in moisture while they finished cooling).
• Trim tops from cake to form an even layer (they are quite domed so you don't need to make it completely level across - just add a little more frosting to the edges that aren't as level so you don't have to cut off so much cake). Add frosting to top of one round then top with second cake and frost top and sides of cake. Store in an airtight container.
• For the chocolate buttercream frosting:
• In a the bowl of an electric stand mixer, fitted with whisk attachment (paddle attachment works too. Whichever you use just pay attention the the shade of the butter), whip butter on moderately high speed until very pale and fluffy (nearly white in color), about 6 - 8 minutes, occasionally scraping down sides of the bowl. Sift in cocoa powder then add in powdered sugar, 3 Tbsp heavy cream and vanilla and mix on low speed until combine, scrapping down the sides of the bowl as needed and adding up to 1 tbsp additional cream to thin if desired. Increase mixer to medium-high speed and whip mixture until pale and very fluffy about 4 - 5 minutes, occasionally scraping down sides of the bowl.
• Note that similar to whipped cream the frosting will lose some of its "fluff" after a few hours, it will still taste the same it just loses some of the air that was whipped into it (similar to whipped cream how it loses it's stabilization after a few hours). It is best to prepare and use within a few hours for best (fluffiest) results.