Preheat the oven to 175ºC /350ºF conventional oven. Prepare 2x 30x40 cm / 12x 16 inch sheet pans with parchment paper. Do NOT grease the sides of the pans as the batter needs to cling to the sides as it rises, which helps the sponge achieve maximum height and a light texture.
Separate the egg whites and egg yolks into two clean bowls. Add the egg whites and white vinegar to the bowl of a stand mixer, using the whisk attachment, or a hand mixer, and beat the egg whites until foamy, on medium speed, then in a slow steady stream pour in the sugar while the egg whites continue to whisk. Continue whisking at high speed until stiff peaks.
10 large egg, ½ teaspoon white vinegar, 320 g granulated sugar
Stir the egg yolks together and add them to the meringue together with the vanilla bean paste. Mix it together at the lowest speed until just combined.
1 teaspoon vanilla bean paste
Sift the all-purpose flour and salt and add it to the meringue. Mix it together at the lowest speed until just combined, it’s important not to over mix the batter.
320 g all-purpose flour, Pinch of salt
Then finally heat up the heavy cream until it starts to steam and pour it into the batter and again mix until just combined.
160 g heavy cream
Give the batter a final mix with a rubber spatula to make sure everything is combined.
Divide the cake batter into the pans and bake them for 11-12 minutes.
Once baked, immediately trace a thin knife along the edge of the pan and flip it upside down, onto a cooling rack. Flip it back around so it faces the right way up.