Roll out pie dough and fit into a 9-inch pie plate.
Place in refrigerator while preparing the filling.
Preheat oven to 400º.
Toss apple with sugar, lemon juice & cinnamon.
Cut butter into flour and sugars.
Pinch with fingers to form large crumbs.
Fill crust with apples.
Sprinkle topping over top of apples.
Place a baking sheet under the rack where the pie will bake to catch any drippings.
Bake for 40 minutes then reduce to 350º for 50 minutes or until bubbling.
Cover crust with foil if browning too quickly.
Cool before slicing.
Serve with vanilla ice cream and whipped cream.