Southern Living: Chocolate Truffle Cake

I think this is one of my mom's favorite cakes.  And after all the work it takes, it certainly should be.  This is a chocolate bomb of ridiculous proportions.  Chocolate cake, chocolate frosting, chocolate truffle filling, chocolate truffles on top.  I'm trying to think how you could stick any more chocolate in this one.  Maybe chocolate fudge drizzled over each slice?

Chocolate Truffle Cake
From Southern Living magazine

Chocolate Truffles
2-3 tablespoons whole milk
Rich Chocolate Cake
Satiny Chocolate Frosting
2 bottles chocolate sprinkles

Prepare the chocolate truffles. Combine the milk and the reserved ¾ of the truffle mixture; beat at high speed until the mixture is spreading consistency. Spread between the layers of chocolate cake. Frost with Satiny Chocolate Frosting. Pat chocolate sprinkles onto the sides of the cake. Arrange the truffles on top. Chill until serving time.

Makes 16 servings

Chocolate Truffles
1 (12-ounce) package semisweet chocolate chips
4 large egg yolks
6 tablespoons unsalted butter, cut into pieces
¼ cup plus 2 tablespoons powdered sugar
2 tablespoons chocolate sprinkles

Melt the chocolate chips in a saucepan; remove from the heat. Beat the egg yolks until thick and lemon-colored. Gradually stir ¼ of the melted chocolate into the yolks; add to the remaining chocolate, stirring constantly. Add the butter and powdered sugar; beat until the butter melts and the mixture is smooth. Place ¼ of the mixture into a small bowl; cover with a paper towel, and let stand in a cool, dry place for 1 hour. Set aside remaining truffle mixture. After ¼ of the mixture has set for 1 hour, shape into 12 balls; roll the balls in chocolate sprinkles.

Rich Chocolate Cake
1 cup unsweetened cocoa powder
2 cups boiling water
1 cup (2 sticks) unsalted butter, softened
2½ cups granulated sugar
4 large eggs
1½ teaspoons pure vanilla extract
2¾ cups all-purpose flour
2 teaspoons baking soda
½ teaspoon baking powder
½ teaspoon salt

Combine cocoa and boiling water, stirring until smooth. Set aside to cool.

Cream the butter, sugar, eggs, and vanilla until light and fluffy (about 5 minutes). Combine the flour, baking soda, baking powder, and salt in a small bowl. Add to the creamed mixture alternately with the cocoa mixture. Beat at low speed, beginning and ending with the flour mixture. Pour into 3 greased and floured 9-inch round cake pans. Bake at 350°F for 25 to 30 minutes. Cool the cakes in the pans for 10 minutes; then remove them from the pans and let cool completely on wire racks.

Satiny Chocolate Frosting
1 (6-ounce) package semisweet chocolate chips
½ cup whole milk
1 cup (2 sticks) unsalted butter
2½ cups powdered sugar

Combine the chocolate chips, milk, and butter in a saucepan; cook over medium heat, stirring constantly, until the mixture is melted and smooth. Remove the pan from the heat; blend in the powdered sugar. Set the pan in a bowl of ice water; beat the mixture until the frosting cools and holds its shape.