Devils Food Cake

The best chocolate cake!

Devils Food Cake
4 oz. unsweetened chocolate, chopped
1/4 C. cocoa
1 1/4 C. boiling water
3/4 C. all purpose flour
3/4 C. cake flour
1 t. baking soda
1/4 t. salt
2 sticks unsalted butter, softened but still cool
1 1/2 C. dark brown sugar, packed
3 large eggs, room temperature
1/2 C. sour cream
1 t. vanilla

Adjust the oven racks to the upper and lower-middle positions; heat to 350 degrees. Meanwhile, grease 3 8" cake pans and line the bottom of each pan with a round of parchment paper. Combine the chocolate and cocoa in a medium bowl, pour the boiling water over and whisk until smooth. Sift together the flours, baking soda and salt onto a large sheet of parchment or waxed paper; set aside.

Beat the butter in the bowl of a standing mixer at medium-high speed until creamy, about 1 minute. Add teh brown sugar and beat at high speed until light and fluffy, about 3 minutes. Stop the mixer and scrape down the bowl with a rubber spatula. With the mixer at med-high speed, add the eggs one at a time, beating 30 seconds after each addition. Reduce the speed to medium; add the sour cream and vanilla and beat until combined. Stop the mixer and scrape down the bowl. With the mixer on low speed, add about a third of the flour mixture, followed by about half the chocolate mixture. Repeat, ending with the flour; beat until just combined, about 15 seconds. Do not overbeat. Remove the bowl from the mixer, scrap the bottom and sides of the bowl and stir gently to thoroughly combine.

Divide the batter evenly among the cake pans and smooth the batter to the edges of each pan. Place 2 pans on the lower rack and 1 on the upper. Bake until a toothpick comes out clean, 20-23 minutes. Cool on wire racks 15-20 minutes. Run a knife around each cake onto a large plate; peel off the parchment and reinvert onto a rack. Cool completely.