Melt the butter. Separate the egg whites from the yolks. Beat the egg whites until stiff peaks form. Meanwhile, beat the yolks with the sugar using a wooden spoon until the mixture is pale and creamy. Add half the flour and gently fold in half of the beaten egg whites. Gently fold in the remaining flour, then the rest of the egg whites, and finally the melted (but not hot) butter.

Spread the batter onto a baking sheet (10x12 inches/25x30 cm) lined with well-buttered parchment paper. Bake in a preheated oven at 410°F (210°C) for 10 minutes. When done, cover with another sheet of parchment paper, flip onto a damp kitchen towel, and roll up the sponge cake. Set aside.

For the raspberry whipped cream: Whip the cream until stiff. Meanwhile, if using frozen raspberries, thaw them quickly, add a small spoonful of brown sugar, and mash together. When the whipped cream is ready, gently fold in the jam. Cut a few strawberries into very small pieces.

To fill the sponge cake: Unroll the cake and lay it flat. Spread a thin layer of mashed raspberries, then the raspberry whipped cream, and finally the small pieces of strawberries.

For the red berry sauce: Heat the berries with the sugar, water, and the third split and scraped vanilla bean. When the berries soften, remove from heat and blend. You can strain the sauce if you like. Chill in the refrigerator.

Vanilla tip: Before preparing and measuring all the ingredients, take out 3 vanilla beans. Split the first one, scrape out the seeds, and add both seeds and pod to the egg whites to infuse while you prepare the rest. Remove the pod just before beating the whites. Do the same with the second bean, adding it to the cream for the raspberry whipped cream.

When ready to serve, decorate your roll with some fruit, powdered sugar, whipped cream, and berry sauce. I served mine with a small glass filled with cake trimmings at the bottom, a few small pieces of strawberries and raspberries, a spoonful of berry sauce, raspberry whipped cream, and vanilla whipped cream. Enjoy!