For Crust: Melt butter and sugar in saucepan. Add flour and stir until mixture forms a ball. Cool slightly and press over bottom and sides of 9" pie plate, shaping edge if desired.
For Pie: Place ingredients in unbaked pie crust (reserving the sour cream) in order: apples first, then sprinkle sugar, flour, salt, cinnamon and nutmeg. Dot top with pieces of butter. Spread sour cream on top.
Bake at 400 degrees F for 25 minutes and lower temperature to 350 degrees F for 25 minutes. Let cool slightly and serve.