Preheat oven to 350º. Line a 9 x 13-inch pan with foil and spray with non-stick cooking spray.½
Sift together the cake flour, sugar, baking powder, and kosher salt into a large mixing bowl. Mix till blended. Add the egg, melted butter, milk, and vanilla. Mix to combine completely.
Press the dough evenly in the bottom of the prepared pan
To prepare the top layer, beat the cream cheese until it’s smooth. Add the eggs, vanilla, and melted butter. Mix until combined. Mix in powdered sugar and mix until smooth....you may have a few small lumps.
Pour the batter on top of the bottom layer. Spread it out evenly.
Bake 35-40 minutes. Sprinkle with reserved powdered sugar when cool.
