Preheat the oven to 160 ° C traditional heat. Whip the egg whites until stiff with a pinch of salt, then set aside. Whisk the egg yolks with the powdered sugar until a foamy mixture is obtained. Incorporate the melted unsalted butter (not hot, just lukewarm).

Scrape the seeds from a vanilla bean and add them to the dough. Sift the flour and gradually incorporate it into the dough. Finally add the lukewarm milk and water. The dough becomes very liquid but this is normal.

Last step: pour the whisked egg whites into the dough, breaking them roughly using a whisk. Pour everything into a 20cm round buttered and floured mold (the snowy whites will rise to the surface). Bake for 55 minutes (cover during cooking if it browns too quickly).

Do not consume immediately, let cool and refrigerate before unmolding (run a blade along the walls to facilitate the operation). Enjoy!