Mile High Chocolate Cake

Mile High Cake with
Mile long directions. You can cheat and use box cake mix, and your favorite frosting rather then butter cream if you want. But be sure to use the Chocolate Glaze!
6 layers of crazy good chocolate.

MILE HIGH CHOCOLATE CAKE
with VANILLA BUTTER CREAM

Ingredients:
Cake   (or 2 of your favorite chocolate cake mixes prepared as directed on box)
1 ¼ cup shot water
¾ cup natural unsweetened cocoa powder
2/3 cup sour cream
2 2/3 cups all purpose flour
2 teaspoons baking powder
1 teaspoon baking soda
½ teaspoon salt
¾ cup(1 1/2 sticks) unsalted butter, room temperature
½ cup solid vegetable shortening room temperature
1 ½ cups sugar
1 cup(packed) dark brown sugar
3 large eggs
1 tablespoon vanilla extract

Vanilla Butter Cream  (or 2 containers of your favorite premade frosting)
5 large egg whites
1 2/3 cups sugar, divided
1 vanilla bean, split lengthwise
1/3 cup water
1 pound(4 sticks) unsalted butter, diced, room temperature

Chocolate glaze
5 ounces high-quality milk chocolate, chopped
5 ounces bittersweet chocolate (54% to 60% cacao), chopped
1 ¼ cups heavy whipping cream
2 tablespoons light corn syrup
2 tablespoons(1/4 stick) unsalted butter, cut into 1/2-inch cubes, room temperature

Special equipment 
(you won't need the thermometers if you are not making the butter cream)
Candy thermometer
Instant-read thermometer
Offset spatula


Directions:

CAKE
Butter three 8-inch-diameter cake pans with 1 1/2-inch-high sides. Line bottom of each pan with parchment paper round; butter parchment. Dust pans with flour; tap out excess. Whisk 1 1/4 cups hot water, cocoa powder, and sour cream in medium bowl until smooth; set aside until mixture is cool, 20 to 30 minutes.

Position rack in center of oven and preheat to 325°F. Sift next 4 ingredients into another medium bowl. Using electric mixer, beat butter and shortening in large bowl until well blended and smooth. Add both sugars; beat until light and fluffy, about 5 minutes. Add eggs 1 at a time, beating until well blended after each addition. Mix in vanilla. Add flour mixture in 3 additions alternately with cocoa mixture in 2 additions, beginning and ending with flour mixture and beating just until incorporated. Divide batter among prepared pans (about 2 3/4 cups batter for each) and smooth tops.

Bake cakes until tester inserted into center comes out clean, 50 to 55 minutes. Cool cakes in pans on racks 20 minutes. Run knife around sides of cakes to loosen. Invert cakes onto racks and cool completely. DO AHEAD Can be made 1 day ahead. Wrap in plastic and store at room temperature. Or just use box cake mix, you will need 2 box mixes. When you fill the cake pans (2 3/4 cups batter in each pan) tap them lightly on the counter, this will help make a denser cake and it will be easier to slice to make the layers.


VANILLA BUTTER CREAM

Combine egg whites and 1/3 cup sugar in large bowl of stand mixer fitted with whisk attachment; scrape in seeds from vanilla bean.

Combine remaining 1 1/3 cups sugar and 1/3 cup water in medium saucepan. Stir over medium heat until sugar dissolves. Attach candy thermometer to side of pan, making sure that bulb of thermometer is immersed in syrup. Increase heat; boil until temperature registers 238°F to 240°F (soft-ball stage), about 5 minutes. Immediately remove syrup from heat (use within 2 minutes).

Meanwhile, beat egg white mixture on medium speed until very soft peaks form (mixture will be slightly opaque).

Increase mixer speed to high and slowly pour hot syrup down side of bowl into egg white mixture in slow steady stream; beat until meringue forms stiff peaks. Cool meringue in bowl until lukewarm (instant-read thermometer will register 100°F), about 30 minutes. Do not beat.

Start beating meringue again on medium speed of stand mixer. Gradually add butter, 2 to 3 tablespoons at a time, beating constantly until absorbed before adding next addition. Continue beating until butter cream is smooth. (If butter cream looks broken or curdled, place mixer bowl with butter cream over medium heat on stove burner and whisk with large whisk for 5 to 10 seconds to warm mixture slightly, then remove from heat and whisk vigorously or attach bowl to stand mixer and beat mixture again on medium speed. Repeat warming and beating butter cream mixture as many times as needed until butter cream is smooth and no longer curdled. Or use your favorite premade frosting, you will likely need about 2 containers.
BACK TO THE CAKE - PREPPING IT AND ADDING FROSTING

Using serrated knife cut each cake in half horizontally, forming 6 cake layers. If necessary, trim any domed tops of cakes to form even layers. Place 1 cake layer on platter. Drop 3/4 cup butter cream by tablespoonfuls over top of cake layer, and then spread evenly to edges with offset spatula. Top with second cake layer, then spread 3/4 cup butter cream over. Repeat with 3 more cake layers, spreading 3/4 cup butter cream over each and pressing slightly to adhere. Top with 6th cake layer (do not spread butter cream over top cake layer). Chill cake at least 1 hour.


CHOCOLATE GLAZE

Combine both chocolates in medium bowl. Bring cream and corn syrup to simmer in heavy saucepan. Pour hot cream mixture over chocolate; let stand 2 minutes. Whisk chocolate mixture until melted and smooth. Add butter; whisk until melted. Chill glaze until slightly thickened and glaze drips thickly when poured slowly from spoon, 30 to 45 minutes.

Spoon glaze around top edge of cake by teaspoonfuls, spacing drips up to 2 inches apart and allowing glaze to drip slowly down sides of cake. Spoon remaining glaze over top center of cake and smooth with offset spatula, covering top completely. Chill cake until glaze sets, at least 1 hour. DO AHEAD Can be made 1 day ahead. Tent with foil and keep chilled. Let cake stand at room temperature 1 hour before serving.