Ingredients:

  • 2 ½ cups (300g) all-purpose flour, plus more for dusting
  • 1 ½ teaspoons baking powder
  • ½ teaspoon baking soda
  • ½ teaspoon salt
  • ¾ cup (1 ½ sticks, 170g) unsalted butter, softened (plus extra for greasing the pans)
  • 1 ¾ cups (350g) granulated sugar
  • 3 large eggs
  • 1 teaspoon pure vanilla extract
  • 1 ¼ cups (300ml) buttermilk
  • 1 ½ cups (3 sticks, 340g) unsalted butter, softened
  • 6 cups (720g) powdered sugar, sifted
  • ½ cup (120ml) heavy cream
  • 2 teaspoons pure vanilla extract
  • Gel food coloring (blue, purple, black, and pink)
  • Edible glitter (silver or white)
  • Assorted star-shaped sprinkles
  • Shimmering candies (e.g., Sixlets, sugar pearls)
  • Optional: Silver or gold edible spray paint

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and flour (or use baking spray) two 9-inch round cake pans. Line the bottoms with parchment paper circles.
  2. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
  3. In a large bowl, cream together the softened butter and sugar until light and fluffy.
  4. Beat in the eggs one at a time, then stir in the vanilla extract.
  5. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined. Do not overmix.
  6. Divide the batter evenly between the prepared cake pans. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
  7. Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely.
  8. In a large bowl, beat the softened butter until light and fluffy. Gradually add the powdered sugar, beating on low speed until combined. Add the heavy cream and vanilla extract, and beat on high speed until smooth and creamy.
  9. Divide the buttercream into four bowls. Tint each bowl with blue, purple, black, and pink gel food coloring.
  10. Level the cake layers if necessary (using a serrated knife). Place one cake layer on a serving plate or cake stand. Spread a thin layer of buttercream (any color) on top. Place the second cake layer on top.
  11. Spread a thin crumb coat of white buttercream over the entire cake. Chill for 30 minutes. Next, using a piping bag or offset spatula, apply dollops of the colored frostings randomly around the cake. Swirl the colors together using an offset spatula.
  12. Sprinkle the cake with edible glitter and star-shaped sprinkles. Add shimmering candies to create a starry effect. Optionally spray lightly with silver or gold edible spray.
  13. Chill the cake for at least 30 minutes before serving.