Preheat the oven to 325°F.
Cut the apples into thin slices and toss with fresh lemon juice to prevent discoloration.
Combine the milk, eggs, sugar, vanilla, cinnamon, salt and butter in a large bowl, whisking until the sugar dissolves. Add the flour, whisking until smooth.
Lightly butter or use non-stick spray10 to prepare a 9 inch or two 6 inch pie pans or cast iron skillets then pour in the batter. Arrange the cut apples on top. Bake in the oven for 35 to 40 minutes until fluffy and golden. Dust with desired amount of powdered sugar, serve immediately.