Preheat your oven to 325 degrees F. Spray two 8-inch round cake pans with nonstick spray, line the bottom with parchment paper and spray again.
In a medium mixing bowl, whisk the flour and the baking powder. Set aside.
In the bowl of an electric mixer, fitted with the whisk attachment, beat the egg whites until stiff peaks form.
Gradually beat in the sugar and then the yolks. Beat in the vanilla.
Switch to the paddle attachment and alternately add the flour mixture with the milk, beginning and ending with the flour mixture.
Evenly pour the batter in the two pans, about 20 ounces in each. Bake for about 25 to 30 minutes.
The cake should rise to the top of the pan and be a little spongy. That's good. We want that texture to soak up the milk soak. Let the cakes cool in the pans.