Vanilla Chiffon Sponge

1. Preheat the oven to 350°F / 180°C and prepare three unlined 6-inch / 15 cm aluminum cake pans. (See notes if baking in two batches.)
2. In a medium bowl, sift together the cake flour, salt, and baking powder at least twice. Set aside.
3. In another bowl, whisk the egg yolks with the vegetable oil, ¾ of the sugar, vanilla extract, and milk until smooth.
4. Add the dry mixture to the wet mixture and whisk until you get a smooth cake batter.
5. In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites on medium-low speed for 2–3 minutes until foamy.
6. Add the cream of tartar and the remaining sugar, then whip on high speed for 3–4 minutes until you reach stiff, glossy peaks.
7. Add a small amount of meringue to the batter and mix quickly to lighten the mixture. Gently fold in the rest with a spatula, working from the center outwards, until smooth and airy.
8. Pour the batter evenly into the three pans and run a knife through to remove air bubbles.
9. Bake on the middle rack for 30–40 minutes, without opening the oven door, until golden brown and a toothpick inserted in the center comes out clean.
10. Remove the pans and let the cakes cool upside down for at least 1 ½ hours.
11. Run a knife around the edges to release the cakes. Wrap tightly in plastic wrap and refrigerate until ready to assemble.

Strawberry Filling

1. In a medium bowl, toss the sliced strawberries with the granulated sugar.
2. Cover and refrigerate for 15–20 minutes, then drain the excess juice before using.

Whipped Cream Frosting

1. In a large mixing bowl, combine the cold heavy cream, powdered sugar, and vanilla extract. (Optional: add cornstarch or cream of tartar for stability.)
2. Whip with a stand mixer or electric hand whisk on medium speed for 3–4 minutes until you have a thick, smooth whipped cream frosting that forms stiff peaks.

Assembly of the Layer Cake

1. Place a cake board on a turntable and set down the first cake layer.
2. Spread a layer of whipped cream, then pipe a border around the edge to hold the filling. Add some strawberry filling in the center and cover with more cream.
3. Add the second cake layer and repeat the process, finishing with the third layer.
4. Cover the whole cake with a thin crumb coat of whipped cream, then smooth with an offset spatula or cake scraper.
5. Decorate the top with the remaining cream using a piping bag and add fresh strawberries.
6. Chill in the refrigerator for at least 1 hour before serving, ideally with a drizzle of homemade strawberry sauce or coulis.