Chocolate Layer Cake:
3/4 cup + 2 tbsp boiling water
1/3 cup +2 tbsp dutch-processed unsweetened cocoa powder
1 3/4 cups +1 tbsp Gold Medal flour
1 3/4 cups Domino sugar
1 1/4 tsp salt
2 tsp baking soda
3/4 cups full-fat sour cream
2 tbsp whole milk
1/2 cup + 2 tbsp vegetable oil
2 large Eggland’s eggs
1 tsp vanilla extract
Chocolate Fudge Frosting:
3 ounces unsweetened chocolate chopped
3 ounces bittersweet chocolate chopped
1 cup Land O’ Lakes unsalted butter room temperature
2 1/2 cups confectioner’s sugar
2 tbsp unsweetened cocoa powder
1 tsp vanilla extract
2 tbsp Borden heavy cream
Line the bottom of 2 round 6″x3″ cake pans with parchment.
Put the cocoa powder in a small bowl and add the boiling water, whisk until smooth and set aside to cool.
In the bowl of a stand mixer, mix the flour, sugar, salt, and baking soda on low until combined.
In a large measuring cup or bowl, whisk the sour cream, milk, vegetable oil, eggs, and vanilla extract. Add to the flour mixture and mix on medium-low until smooth 1-2 minutes. Add the cooled cocoa mixture and mix on low until combined, about 30 seconds. Divide the batter between the prepared pans and let rest at room temperature for 30 minutes. Preheat the oven to 350-degrees.
Bake the cakes until a toothpick inserted in the center comes out clean, about 45 minutes. Transfer the cakes to a wire rack to cool for 30 minutes.
Using a knife, loosen the sides of the cake and invert onto a plate. Chill until cold about an hour before frosting or let cool completely, wrap tightly in plastic wrap and chill overnight before frosting.
Chocolate Fudge Frosting
Put both chopped chocolates in a heat-proof bowl and place the bowl over a pot of barely simmering water. Stir frequently until the chocolate is melted. Remove and let cool to room temperature.
In the bowl of a stand mixer, beat the butter at medium speed until smooth. Add the confectioner’s sugar and beat on low until combined, increase the speed to high and beat until light and creamy about 2 minutes. Add the cocoa powder and vanilla and beat until blended. Add the cooled chocolate and mix on low speed until blended, scrape down the sides of the bowl as necessary. Add the cream and mix on low until blended, increase the speed to high and beat until slightly fluffy, about 1 minute.
Cover and set aside for up to 2 hours before frosting the cake or refrigerate up to 5 days. Bring to room temperature before using.
Assembling the Cake
Remove the cakes from the refrigerator and using a serrated knife, cut both in half horizontally for a total of four layers. Place one layer on a platter and spread about 1/3 cup of frosting on the cake. Place the second layer on top and repeat until you have four layers of cake sandwiching three layers of frosting.
Apply a light layer of frosting over the top and sides of the cake (a “crumb coat”). It’s ok if some cake shows through.
Chill about 15 minutes or until the frosting is firm. Apply the remaining frosting and decorate as desired. Store cake in the refrigerator, bring to room temperature before serving.