Preheat & Prep Pans: Preheat oven to 170 °C (338 °F). Line two 6‑inch round cake pans with parchment, butter sides, and dust with flour.
Whip Eggs & Sugar: In a grease‑free bowl, beat eggs and granulated sugar on medium‑high until pale and ribbon‑stage (6–8 min).
Fold in Dry Ingredients: Gently fold sifted cake flour, cornstarch, and salt into the egg mixture in three additions, using a rubber spatula to preserve air.
Add Butter & Milk: Temper melted butter, warm milk, and vanilla by whisking in a few spoonfuls of batter, then fold back into the main batter until combined.
Bake the Sponge: Divide batter between pans, tap out bubbles, and bake 18–22 min until a skewer comes out clean. Cool inverted on racks.
Prepare Strawberries: Wash, hull, and pat strawberries dry. Slice most for filling; reserve whole berries for decoration.
Make Whipped Cream: Chill bowl and beaters. Whip cold cream, powdered sugar, and vanilla on medium to firm peaks—avoid overbeating.
Assemble Layers: Place one sponge on a cake board. Brush with simple syrup if using. Spread a thin layer of cream, arrange strawberry slices, then seal with another thin cream layer. Top with second sponge.
Crumb Coat & Chill: Apply a thin “crumb coat” of cream; chill 15 min.
Final Frosting & Decorate: Frost cake smoothly with remaining cream using an offset spatula. Arrange whole strawberries around the top edge, pipe cream rosettes between, and dust with powdered sugar.