Preheat oven to 400 degrees F. Divide butter evenly between two 9 inch pie plates and put them in the oven to melt the butter. Remove the plates and rotate them so the melted butter coats the bottom and the sides. Set aside.
Beat eggs, flour, milk and salt at medium speed for one minute. Arrange half of the apple slices in each pie plate. Pour half the egg mixture over the apple slices in each pan.
Mix the cinnamon and sugar together and sprinkle over the top of each pan.
Bake until puffed and golden brown, 20-25 minutes. Serve immediately with warm syrup.