Separate the egg whites and yolks. Place the yolks in a bowl, add 1/2 cup sugar (about 100 grams) and beat until dissolved. Next, add the oil and milk, mix well. Sift the flour and cornstarch together, then add to the yolk mixture and beat well. Finally, add the vanilla and mix.

In another bowl, use a mixer to beat the egg whites with a pinch of salt and lemon juice (as a substitute for cream of tartar) until large bubbles form. Gradually add the remaining sugar and beat until the egg whites are stiff, glossy, and slightly elastic.

Fold 1/3 of the beaten egg whites into the yolk mixture to lighten it. Gradually fold in the remaining egg whites, gently mixing from the bottom up to combine the two mixtures. Line the bottom of a round pan with parchment paper, pour the batter into the pan, and gently tap the pan on the counter to remove large air bubbles and even out the batter.

Bake in a preheated oven at 350°F (about 180°C) for about 30 minutes, depending on the size of the oven.