Cake batter

1. Preheat your oven to 325°F (165°C) and line three 6-inch round cake pans with parchment paper. Lightly grease the sides to prevent sticking.
2. Whisk together the dry ingredients – cake flour, cornstarch, baking powder, baking soda, and salt – in a medium bowl and set aside.
3. In the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter and granulated sugar on medium-high speed for about 3 minutes, until light and fluffy.
4. Add the egg whites one at a time, mixing well after each addition. Pour in the vanilla extract and beat for another 3–5 minutes until the mixture looks smooth and airy.
5. Reduce the speed to low and add the dry ingredients and buttermilk in 3 additions, alternating between the two. Begin and end with the dry ingredients. Mix just until combined — don’t overmix.
6. Divide the batter evenly between the prepared pans and smooth the tops with a spatula.
7. Bake for about 30 minutes, or until a toothpick inserted in the center comes out clean.
8. Let the cakes cool for 10 minutes, then carefully remove them from the pans.
9. Turn the cakes upside down on a wire rack to finish cooling completely — this helps keep the layers perfectly flat and moist.

Strawberry filling

Follow the strawberry purée recipe and leave to cool completely in the fridge.

Swiss buttercream frosting

Follow the Swiss meringue buttercream recipe and leave at room temperature until ready to assemble.

Assembling the Layer Cake

1. Using a sponge knife and a sponge cake leveler, cut out the bumps and remove the crusts, if necessary, from the 3 cake layers.
2. Place a first layer of cake on a cake board, then on a cake turntable.
3. Apply buttercream frosting around the edges to form a boudin and spread also a small layer of buttercream over the cake layer.
4. Fill the inside with cooled strawberry filling and top with the second layer of cake, and repeat until you reach the last layer.
5. Apply a thin layer of buttercream frosting over the whole cake and smooth with an angled spatula, then place the cake in the fridge for 20 minutes.
6. Apply a new layer of buttercream frosting over the whole cake and smooth with a stainless steel icing smoother.
7. Decorate the top of the cake with the remaining buttercream frosting in a piping bag with a star tip.
8. Garnish the top center with strawberry filling and decorate with fresh strawberries before serving.