Preheat oven to 350°F.
On a floured surface, roll out the pie crust dough into a large circle and place it into a 9-inch deep-dish pie plate, cutting away any excess crust. (If using a smaller pie pan, you will need to adjust the baking time.)
Flute or crimp the edges and place the crust in the refrigerator while you prepare the filling.
In the bowl of a food processor, add cranberries, sugar, and flour. Pulse until the berries are slightly smashed.
Spoon the cranberry filling into pie crust.
In a small bowl, combine walnuts, brown sugar, flour, and shortening. Use a fork or a pastry blender to mix together until crumbly.
Sprinkle the streusel mixture over the pie.
Place a baking sheet under the pie pan to catch any spills. Bake the pie 55-60 minutes, or until the crust is golden and the filling is bubbly.
Let the pie cool before slicing and serving.