Mix the butter and sugar until well combined.
Add the egg yolks.
Add the vanilla.
Add the milk.
Combine the flour, baking powder, salt in another bowl.
Slowly add to the flour mixture, while continuing to mix.
Beat the egg whites separately, Once peaks form you are done.
Fold in the egg whites with the milk mixture.
Spray two nine inch glass plates.
Pour mixture into the pie plates.
Bake at 375 degrees for 20 minutes.
Turn temperature down to 350 degrees and bake for 25 minutes.
Let cool completely before serving.
Sprinkle with cinnamon sugar.