Beat the egg whites until frothy, add 2 tbsp sugar, and continue beating to stiff, glossy peaks.

Whisk the egg yolks, remaining sugar, and vanilla until thick. Warm the milk and melted butter together, stir into the yolk mixture, then sift in the cake flour and whisk smooth. Fold in the egg whites in three additions until no streaks remain.

Preheat the oven to 350°F (175°C). Line a 6-inch square pan with parchment, scrape in the batter, and bake 18 to 20 minutes until the top springs back. Cool in the pan 5 minutes, then lift out and cool completely on a rack.

Whip the cold cream, powdered sugar, and vanilla until stiff peaks form. Keep chilled.

Slice the cooled cake horizontally into two even layers. Spread just under half the cream on the bottom layer, arrange sliced strawberries on top, then place the second layer and spread the remaining cream over it.

Finish the top with a few neat strawberry slices and serve soon after, while the berries look fresh.