Butter your baking dish thoroughly and preheat your oven to 390F or 200C. Whip the egg yolks with 10g (1/3 oz) of the sugar and the vanilla extract foamy. In a mixer, beat the egg white to a hard peak and during this process, slowly add the remaining sugar little by little until all the sugar is well incorporated and the mixture is very stiff. The stiffness of the egg white will be the critical success factor of this dish. You must ensure that the sugar/egg white mixture is really whipped to a hard peak.

Gently fold the egg yolk mixture under the egg white mixture, then add the flour little by little until the fully incorporated.

Add the lemon juice just before scooping the mixture into the baking dish.

Scoop the mixture in heaps into the baking dish and bake just as is, do not flatten or smoothen, but rather ensure that the surface still has peaks when starting to bake.

Bake in the oven for 10-12 minutes, depending on the dish/dishes chosen, until golden brown. Dust with icing sugar and serve at once.