Ingredients:

  • 2 cups (475ml) Brut Champagne or sparkling wine
  • 1 tbsp (15ml) Vanilla bean paste
  • 3 cups (375g) Cake flour, sifted
  • 1 ½ cups (300g) Granulated sugar
  • 1 ½ tsp Baking powder
  • ½ tsp Baking soda
  • 1 tsp Salt
  • 1 cup (225g) Unsalted European-style butter, room temperature/cubed
  • 4 Large egg whites, room temperature
  • ½ cup (120ml) Sour cream, full fat
  • ½ cup (120ml) Reserved champagne reduction
  • 1 ½ cups (340g) Unsalted butter, softened
  • 4 cups (500g) Powdered sugar, sifted
  • 3 tbsp (45ml) Reserved champagne reduction
  • 1 pinch Fine sea salt
  • Edible gold leaf and gold sprinkles (for decorating)

Instructions:

  1. Simmer 2 cups of champagne in a small saucepan over medium heat until reduced to approximately ¾ cup (about 15–20 minutes). Cool completely before using.
  2. Preheat oven to 350°F (175°C). In a stand mixer, whisk together cake flour, sugar, baking powder, baking soda, and salt. Add cubed butter one piece at a time on low speed until the mixture resembles coarse sand.
  3. Whisk egg whites, sour cream, and ½ cup of the cooled champagne reduction. Gradually pour into the dry ingredients while mixing on medium. Beat for 60 seconds until fluffy. Divide into pans and bake for 30–35 minutes.
  4. Whip the buttercream butter, powdered sugar, 3 tbsp champagne reduction, and salt until light and airy. Stack cooled layers with frosting, apply a crumb coat, chill, then finish with remaining frosting and edible gold decoration.