Ingredients:

  • 3 cups (375g) cake flour
  • 1.5 tsp (7g) baking powder
  • 0.5 tsp (3g) baking soda
  • 1 tsp (5g) fine sea salt
  • 1 cup (225g) unsalted butter, softened
  • 1.75 cups (350g) granulated sugar
  • 4 large (200g) eggs, room temperature
  • 1 tbsp (13ml) vanilla bean paste
  • 1 cup (240ml) full-fat buttermilk, room temperature
  • 5 large (150g) egg whites
  • 1.5 cups (300g) granulated sugar
  • 1.5 cups (340g) unsalted butter, softened and cubed
  • 2 tsp (10ml) vanilla extract
  • 1g salt
  • Gel food coloring

Instructions:

  1. Preheat the oven to 350°F (175°C). Grease a 9x13 inch baking pan and line the bottom with parchment paper.
  2. Cream the softened butter and sugar on medium-high speed until pale and fluffy, approximately 3 minutes.
  3. Add eggs one at a time, beating well after each addition, then stir in the vanilla bean paste.
  4. In a separate bowl, whisk together the cake flour, baking powder, baking soda, and salt.
  5. Alternately add the dry ingredients and the buttermilk to the butter mixture, starting and ending with the flour. Mix on low speed until just combined.
  6. Pour the batter into the prepared pan and bake for 30-35 minutes until a toothpick inserted in the center comes out clean.
  7. For the frosting, whisk egg whites and sugar in a heat-proof bowl over a pot of simmering water until the sugar is dissolved and the mixture reaches 160°F (71°C).
  8. Remove from heat and whip on high speed until stiff peaks form and the mixture has cooled.
  9. Incorporate cubed butter and vanilla extract, whipping until silky and smooth. Add gel food coloring as desired.
  10. Frost the cooled cake and chill for 2 hours to set the frosting before serving.