Streusel:

2/3 cup walnuts

1/2 cup (packed) golden brown sugar

1/4 cup yellow cornmeal

1/4 cup all purpose flour

3/4 teaspoon ground cinnamon

1/2 teaspoon ground nutmeg

5 tablespoons chilled unsalted butter, cut into small pieces

  Filling:

2 1/4 pounds Granny Smith apples (about 6 medium), peeled, quartered,

      cored, cut into 1/2-inch-thick wedges

1/2 cup sour cream

1/4 cup sugar

2 tablespoons all purpose flour

1 1/2 teaspoons ground cinnamon

3/4 teaspoon ground nutmeg

1/4 teaspoon ground cloves

1 Flaky Pie Crust

Vanilla ice cream

For streusel: Combine nuts, brown sugar, cornmeal, flour, cinnamon and nutmeg in

processor. Using on/off turns, process until nuts are finely chopped. Add butter and

process until small moist clumps form. (Can be prepared 1 day ahead. Cover and

refrigerate.)

For filling: Position rack in center of oven and preheat to 375°F. Toss apples with sour

cream in large bowl to coat. Mix sugar, flour, cinnamon, nutmeg and cloves in small

bowl. Sprinkle mixture over apples and toss to coat.

Transfer filling to prepared crust. Sprinkle streusel over apples, covering completely.

Bake pie until apples are tender and streusel is golden, tenting pie with foil if streusel

browns too quickly, about 1 hour. Transfer pie to rack and cool slightly.

Serve pie slightly warm or at room temperature with vanilla ice cream.