Ingredients
For the Cake:
| Ingredient | Amount |
|---|---|
| All-purpose flour | 2 ¼ cups (280 g) |
| Baking powder | 2 ½ teaspoons |
| Salt | ½ teaspoon |
| Unsalted butter (softened) | ¾ cup (170 g) |
| Granulated sugar | 1 ¾ cups (350 g) |
| Egg whites (room temp) | 4 |
| Vanilla extract | 1 teaspoon |
| Whole milk (room temp) | 1 cup (240 ml) |
For the Frosting:
| Ingredient | Amount |
|---|---|
| Unsalted butter (softened) | 1 cup (230 g) |
| Powdered sugar (sifted) | 4 cups (500 g) |
| Vanilla extract | 2 teaspoons |
| Heavy cream or milk | 2–4 tablespoons |
Instructions
- Preheat the Oven
Set your oven to 350°F (175°C). Lightly grease and flour a 9×13-inch pan or line it with parchment for easy removal. - Prepare the Dry Mix
In a medium bowl, whisk together flour, baking powder, and salt. Set aside. - Cream the Butter and Sugar
In a large bowl, beat the softened butter with the sugar until the mixture is pale and fluffy, about 2 to 3 minutes. - Add Egg Whites and Vanilla
Beat in the egg whites one at a time, making sure each is fully incorporated before adding the next. Stir in the vanilla extract. - Combine Wet and Dry
Alternately mix the dry ingredients and milk into the butter mixture, beginning and ending with the flour. Stir until just combined—avoid overmixing. - Bake the Cake
Pour the batter evenly into the prepared pan and smooth the top. Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool fully before frosting. - Prepare the Frosting
In a large bowl, whip the softened butter until smooth and creamy. Slowly beat in the powdered sugar. Add vanilla and cream (or milk) a tablespoon at a time until the frosting reaches your desired consistency. - Frost and Enjoy
Spread the frosting over the completely cooled cake. Cut into squares and serve.
Baking Tips
- Use Room Temperature Ingredients
Ensure your butter, egg whites, and milk are all at room temperature to create a smooth, well-emulsified batter. - Extra Airiness
For a fluffier cake, try whipping the egg whites to stiff peaks separately and gently folding them in at the end. - Flavor Variations
Add a layer of your favorite fruit jam or some fresh berries between the cake and frosting to add a fruity twist.