Inspired by the sapphire birthstone, this triple chocolate fudge cake dazzles with rich flavor and a celestial purple-blue design. Accented with edible gold pearls and hints of a starry night, it's a decadent showstopper perfect for September celebrations or anyone who loves a touch of magic with their chocolate.
Heat oven to 350°F. Grease and flour two 6-inch round cake pans.
Prepare cake batter as directed on the package. Divide batter evenly between pans.
Bake 35 to 40 minutes, or until a toothpick inserted into the center comes out clean. Cool 10 minutes; remove from the pans and place on a cooling rack. Cool 30 minutes at room temperature. Place cake layers in the freezer for 20 to 30 minutes or until chilled but not completely frozen.
In a large bowl, beat softened butter with an electric mixer on medium-low speed for 2 to 3 minutes or until smooth and creamy. Add powdered sugar in batches, beating until smooth after each addition. Add vanilla, beat until well blended.
Place 1/2 cup of the frosting into a piping bag fitted with a coupler; set aside. Add the purple food color to the remaining frosting; mix thoroughly.
Place 1/2 cup of the purple frosting into a piping bag fitted with a coupler; set aside. Add the blue food color to the purple frosting to create sapphire blue frosting.
Using a serrated knife or a cake leveler, cut rounded tops off cake layers to create a level surface.
Spread a layer of the blue frosting on top of one of the cake layers; top with the second cake layer. Spread a thin coat of blue frosting over entire cake to lock in the crumbs. Freeze for 10 minutes.
Frost the entire cake with another coat of blue frosting. Place remaining blue frosting in a piping bag fitted with a coupler.
Use a round piping tip (such as #10) to pipe white clouds at the bottom of the cake. Use an open star piping tip (such as #32) for the purple border around the top of the cake and accent decorations, and a leaf piping tip (such as #112) to create blue ruffles along the sides of the cake.
Pipe a little white moon on top of the cake and add edible gold pearls to the cake as desired.
