Galaxy Layer Cake
Moist layers of flavourful black velvet cake filled with fluffy cream cheese filling and fresh blackberries, frosted in gloriously purple vanilla bean frosting and finished with Sweetapolita Galaxy Twinkle Sprinkle Medley and buttercream poofs.
Ingredients
For the Black Velvet Cake layers (Red Velvet Cake variation from The Sweetapolita Bakebook:
  • 3 cups 345 g cake flour, sifted
  • 1 teaspoon baking powder
  • 1 teaspoon Dutch-process dark cocoa powder
  • 3/4 teaspoon salt
  • 1/2 cup 115 g unsalted butter, room temperature
  • 2 cups 410 g superfine sugar (see Notes)
  • 1/2 cup 120 ml vegetable oil
  • 2 tablespoons Red Velvet Bakery Emulsion see Notes
  • 2 teaspoons AmeriColor Soft Paste Gel Color in Super Black
  • 3 large eggs room temperature
  • 1 1/2 cups 360 ml buttermilk, room temperature
  • 1 teaspoon baking soda
  • 2 teaspoons distilled white vinegar
For the Cream Cheese Filling (Fluffy Cream Cheese Frosting from The Sweetapolita Bakebook):
  • 1/2 cup 115 g unsalted butter, room temperature
  • 1 1/2 cups 190 g confectioners' sugar
  • 1 teaspoon pure vanilla extract
  • 1/4 teaspoon pure lemon juice
  • Pinch of salt
  • 1 8oz/250 g package cream cheese, softened and cut into cubes
  • 2 cups about 1 pint fresh blackberries, washed and dried
For the Vanilla Bean Bakery Frosting (adapted from The Sweetapolita Bakebook):
  • 1 1/2 cups 345 g unsalted butter, room temperature
  • Pinch of salt
  • 615 g confectioners' sugar
  • 3/4 cup 180 ml heavy cream (whipping cream)
  • 2 teaspoons vanilla bean paste OR pure vanilla extract
  • Few drops of each AmeriColor Soft Gel Paste Color in Electric Purple and Regal Purple
  • 1 8 oz bottle 1 cup [Sweetapolita Galaxy Twinkle Sprinkle Medley OR sprinkles of your choice
You will also need:
  • 1 large pastry bag disposable or reusable
  • Large plain round pastry tip I use Ateco #809
Instructions
For the Black Velvet Cake:
  1. Preheat the oven to 350°F (180°C). Grease the bottom of three 8 x 2-inch round cake pans and line with parchment.
  2. In a large bowl, sift together the flour, baking powder, cocoa powder and salt. Set aside.
  3. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter, sugar, oil, emulsion and black color on medium speed until very light and fluffy, 5-7 minutes. Add the eggs one at a time, mixing for 20 seconds and scraping the sides of the bowl with a rubber spatula after each addition. Reduce the mixer speed to low and add one-third of the flour mixture until just combined. Repeat until all of the flour mixture and buttermilk have been added. Gently whisk the mixture until smooth.
  4. In a small bowl, combine the baking soda and vinegar, and quickly whisk it into the batter. Divide the batter even among the prepared pans. (If using a scale, each pan should contain about 450 g of batter).
  5. Bake two pans in the center of the oven until a wooden pick inserted into the center comes out with a few crumbs, 20 to 25 minutes. Repeat with the final layer. Let the cake layers cool in their pans on wire racks for 10 minutes. Using a knife, loosen the sides of the cakes and carefully turn them out onto wire racks. Peel off the papers and let cool completely. The cake layers will keep wrapped tightly in plastic wrap at room temperature for up to 2 days.
For the Cream Cheese Filling:
  1. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter on medium speed for 5 minutes. Add the confectioners' sugar, vanilla, lemon juice and salt; decrease the speed to low and beat for 1 minute.
  2. Increase the speed to medium and beat until fluffy, about 4 minutes. Reduce the speed to medium-low, add the cream cheese and beat until smooth, about 1 minute. (Try not to over-beat at this stage, as the cream cheese will cause the frosting to become very thin.) The frosting will keep covered at room temperature for up to 6 hours, and then refrigerated in an airtight container for up to 3 days. Bring chilled frosting to room temperature and beat on low speed to soften.
For the Vanilla Bean Bakery Frosting:
  1. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and salt on medium speed until very pale and creamy, 8 minutes. Reduce the speed to low, and gradually add the confectioners' sugar, heavy cream and vanilla bean paste. Beat for 1 minute.
  2. Increase the speed to medium-high and beat until very light and fluffy, about 6 minutes. Add a few drops of each AmeriColor Regal Purple and Electric Purple until desired shade is achieved. Frosting with keep in an airtight container in the refrigerator for up to 3 days. Bring chilled frosting to room temperature and beat on low speed to soften. If necessary, you can warm the frosting in a heatproof container in the microwave in 10-second intervals, stirring after each one, until smooth and spreadable.
Assembly of the Galaxy Layer Cake:
  1. Put your first cake layer top-up on an 8" round cake board or 10" plate, and spread half of the Cream Cheese filling evenly across the layer. Place one half of the blackberries atop the filling and gently press down to secure. Put the second cake layer (top-up) on top and repeat with another layer of filling and berries. Put the final cake layer top-down. Make sure that your layers are straight and lined up with the ones below. Wrap the cake in plastic wrap and chill for at least 15 minutes.
  2. Remove the cake from the fridge and, using a turntable, if possible, frost entire outside of cake with a thin layer of the purple frosting to seal in the crumbs. Chill until the frosting begins to firm-up, about 30 minutes.
  3. Remove the cake from the fridge and return it to the turntable. Cover the cake with a thick, even and smooth layer of the frosting using an offset spatula, reserving about 1 1/2 cups of frosting for the piped top border. Return the cake to the fridge and chill for another 20-30 minutes.
  4. You will want the frosting for the buttercream "poof" border to be very soft, in order to achieve the appealing peaks. Warm frosting in a small heatproof bowl for about 8-10 seconds, and stir. Fill a pastry bag fitted with a large plain round tip with the softened frosting and pipe some buttercream "poofs" around the top perimeter of the cake.
  5. Pour your sprinkles into a medium bowl and gently press sprinkles onto the bottom third of the cake, all the way around, letting the excess fall back into the bowl. Return the cake to the fridge until the buttercream poofs are very firm, about 30 minutes. Pour more sprinkles atop the flat exposed surface of the top of the cake. Cake will keep covered at room temperature for up to 1 day, or chilled for up to 3 days. Serve at room temperature.
Sweetapolita's Notes

1. Superfine sugar is finer granule regular sugar: You can purchase it superfine or you can simply pulse regular granulated sugar in your food processor for a minute. Superfine sugar lends to a finer crumb and tender cake. That said, you can also use regular sugar--the cake will still be wonderful!

2. Red Velvet Bakery Emulsion: This product from Lorann Oils adds a gorgeous deep red hue and subtle citrus flavour that make this cake unique and tasty. But don't worry if you can't get your hands on any--this cake recipe is still dynamite the old-fashioned way: add 1 tablespoon pure vanilla extract plus 3 tablespoons red liquid food colouring in place of the emulsion.