Combine the egg yolks, salt, and 50 grams sugar. Whisk until light in color and has doubled in size. Set aside.
Beat the egg whites until stiff peak while adding the 70 grams sugar in 3 parts.
Fold the egg yolk mixture to the meringue until combined.
Add the sifted cake flour and baking powder to the batter, folding until all the flour is absorbed.
Combine the milk and vegetable oil in a bowl.
Put some of the batter mixture to the liquid and mix until combined then pour it back to the mixture. Fold until just incorporated.
Pour into your pan and bake in the preheated oven for 20 minutes.