Preheat the oven to 320°.
Separate eggs whites and yolks (make sure you don't get any yolk in the white or the recipe won't work!)
Whip the egg whites and slowly drizzle the sugar into the whites until they reach a medium to stiff peak consistency.
Mix together the vanilla extract and egg yolks.
Fold in the egg whites into the yolks by folding half of the egg white mixture into the yolks, then fold the remaining the whites into egg mixture. Be gentle as you do this, you don't want to deflate the mixture.
Fold the all purpose flour and baking powder into the egg mixture gently.
Then mix in the vegetable oil and milk.
Line the 8 x 8 baking sheet with parchment paper and pour the batter in.
Bake for 14 – 16 minutes, the cake bakes very quickly but will still be a little soft and pale so take it to the 12 minute mark before you pull it from the oven. Let it take on a very pale golden color before you remove it.Let the cakes cool fully before you ice and stack them.