Preheat oven to 375 degrees F (190 degrees C). Melt the butter in a saucepan. Stir in flour to form a paste. Add white sugar, brown sugar, cinnamon and nutmeg; stir until well blended. Arrange the apple slices in the unbaked crust and pour the sugar and butter mixture over them.
Bake at 375 degrees F (190 degrees C) for 35 to 45 minutes, or until apples are soft.