Position rack in center of oven. Set a heavy duty rimmed baking sheet on rack and heat oven to 350. In medium bowl, mix flour, sugar, walnuts and salt. Using your fingers, blend butter into flour mixture. Set aside. To make filling, peel, quarter and core each apple. Cut each quarter lengthwise into 1/4 inch thick slices and then cut each slice crosswise at 1/4 inch intervals to make tiny rectangles. In food processor, pulse cranberries with 3/4 cup of the sugar until coarsely chopped. In large bowl, mix the remaining 6 T. sugar with flour, ginger, cardamom, and cinnamon, breaking up ginger clumps with your fingers. Toss in cranberry mixture and apples. Mound filling into piecrust. Sprinkle streusel topping over apple mixture, pressing streusel between your fingers into small lumps as you sprinkle. Put pie on heated baking sheet and bake until streusel is deeply browned and the filling is bubbling vigorously at the edge of the pie, 65 to 75 minutes. Check every 20 minutes, and if pastry edge or streusel browns before filling is done, loosely cover top or edges of pit as needed with foil. Transfer to a rack and cool completely before serving. Pie can be stored at room temperature for up to 2 days.
Note: A blind baked pie shell is one that has been partially baked.