Step 1

Crust: Combine flour, sugar, cinnamon, and salt. Cut in butter using a pastry blender or two forks. Add water and toss with fork until evenly moistened. Form into a ball and place on a lightly floured surface. Roll the dough to about a 1/4-inch thickness and place in a 10-inch pie plate. Cut off any excess dough and pinch around the edges. Set aside.

Step 2

Filling: Preheat oven to 450°F. In a large bowl, combine apples, sour cream, sugar, flour, egg, vanilla, and salt. Mix well. Spoon into piecrust. Bake 10 minutes. Reduce oven to 350°F and continue to bake for 40 minutes or until filling is golden and slightly puffed.

Step 3

Streusel: Meanwhile, combine nuts, flour, sugars, cinnamon, and salt in a medium bowl. Mix very well. Cut in butter until mixture is crumbly. Spoon over top of pie and bake 15 minutes longer at 350°F.