Arrange a rack in the lowest slot of your oven. Heat oven to 375°F. Fit piecrust into a 9-inch pie plate and decoratively crimp edge. Refrigerate until you are ready to add filling.
Combine flour, brown sugar, cinnamon, salt and cloves in bowl. Rub in butter with fingertips until crumbly. Stir in nuts, if using.
In a large bowl, toss together apples, brown sugar, flour, cinnamon and cloves.
Spoon filling into pie shell, mounding slightly in the center. Top filling with crumb topping. Place on small foil-lined baking sheet.
Bake at 375°F for 30 minutes. Reduce temperature to 350°F; bake 30 minutes more, until fruit is tender. Loosely tent pie with aluminum foil during last 20 minutes. Let cool for at least 1 1/2 hours. (Can be made a day ahead. Cover pie and store at room temperature.) Dust with confectioners sugar before serving.
