Thaw escalloped apples in microwave at MEDIUM (50% power) 6 to 7 minutes.
Microwave cranberries, brandy, and 2 tablespoons water in a large glass bowl at HIGH 2 1/2 minutes; stir in escalloped apples. Add 1/4 cup brown sugar and 3 tablespoons flour, stirring to blend. Set aside.
Combine remaining 1/3 cup flour and 1/3 cup brown sugar in a bowl; cut in butter with a pastry blender until crumbly. Stir in walnuts.
Unfold piecrusts; stack on a lightly floured surface. Roll into a 15-inch circle. Place on a lightly greased baking sheet. Spoon apple mixture in center of pastry, leaving a 3-inch border. Sprinkle with walnut mixture. Lift pastry edges, and pull over apple mixture, leaving a 9-inch circle of fruit showing in center. Press folds gently to secure.
Bake at 400° on lower oven rack for 30 minutes.
*6 tablespoons apple juice concentrate may be substituted.
NOTE: For testing purposes only, we used Ocean Spray Craisins Sweetened Dried Cranberries.