Ingredients:
- 2.5 cups cake flour
- 1.5 cups granulated sugar
- 1 tbsp baking powder
- 0.5 tsp salt
- 0.75 cup unsalted butter, softened
- 4 large egg whites, room temperature
- 1 cup whole milk, room temperature
- 2 tsp pure vanilla extract
- 2 cups heavy whipping cream, cold
- 8 oz cream cheese, softened
- 0.5 cup powdered sugar
- 1 tsp vanilla extract
- 1 pint fresh strawberries, hulled and sliced
- 1 pint fresh blueberries, firm and dry
Instructions:
- Preheat oven to 350°F (180°C). Grease a 9x13 inch baking pan and line with parchment paper.
- Beat softened butter and granulated sugar on medium-high until pale and fluffy.
- Gradually add egg whites one at a time, beating well after each addition, then stir in 2 tsp vanilla extract.
- Alternately add the sifted cake flour mixture and the milk, beginning and ending with flour. Mix only until combined.
- Pour batter into the pan and bake for 30–35 minutes until a toothpick comes out clean. Cool completely on a wire rack.
- Beat softened cream cheese and powdered sugar together until smooth, then stir in 1 tsp vanilla extract.
- Whip cold heavy whipping cream to stiff peaks and fold gently into the cream cheese mixture to create stabilized frosting.
- Spread frosting evenly over the cooled cake using an offset spatula.
- Pat berries dry with paper towels. Arrange strawberries and blueberries on top of the frosting to create an American flag design.
- Chill the cake for 2 hours before serving to ensure the frosting is set.