Preheat oven to 350°F (175°C) and line a 10x15-inch jelly roll pan with parchment paper.
Lightly grease the parchment paper.
In a bowl, beat egg yolks with half the sugar until pale and thick.
Stir in vanilla extract.
In a separate bowl, beat egg whites with a pinch of salt until foamy.
Gradually add remaining sugar and whip until stiff peaks form.
Gently fold egg whites into yolk mixture.
Sift in flour and baking powder, then fold carefully to maintain airiness.
Spread batter evenly into prepared pan.
Bake for 10–12 minutes until lightly golden and springy to the touch.
Turn cake onto a powdered sugar-dusted towel and peel off parchment paper.
Roll cake gently with the towel from the short side and let cool completely.
Whip cream with powdered sugar until soft peaks form.
Unroll cake, spread whipped cream evenly, and add sliced berries.
Roll cake back up gently (without towel).
Dust with powdered sugar and slice to serve.