2 1/4 cups all-purpose flour
3/4 teaspoon salt
2/3 cup butter-flavored shortening
8 - 10 tablespoons cold water
2/3 cup sugar
1/3 cup all-purpose flour
1 teaspoon ground cinnamon
3 1/2 pounds tart cooking apples (such as Rome Beauty or Granny Smith), peeled, cored, and cut into 1/4-inch-thick slices (10 cups)
1 cup quick-cooking rolled oats
1 cup packed brown sugar
1/2 cup all-purpose flour
1/2 cup butter
1/2 cup pecans
Line a 15x10x1-inch baking pan with 18-inch-wide foil, extending the foil up over the edges of the pan; set aside. For dough: In a large bowl, stir together the 2-1/4 cups flour and the salt. Using a pastry blender, cut in shortening until mixture resembles coarse crumbs. Sprinkle 1 tablespoon of the cold water over part of the flour mixture; gently toss with a fork. Push moistened dough to side of bowl. Repeat, using 1 tablespoon cold water at a time, until all of the flour mixture is moistened. Using your fingers, gently knead the dough just until a ball forms.
Preheat oven to 375F. On a lightly floured surface, roll dough into a 19x13-inch rectangle. Wrap it around the rolling pin; unroll it into the prepared baking pan. Ease dough into the pan and up the sides, being careful not to stretch it. Trim dough to 1/2 inch beyond edge of pan. Fold dough edge over and flute as desired.
In an extra-large bowl, combine sugar, the 1/3 cup flour, and the cinnamon; add apples. Toss lightly until apples are coated. Spoon apple mixture into dough-lined pan; spread evenly. Sprinkle with Crumb Topping (pan will be full).
Bake for 40 to 45 minutes or until apples are tender. If necessary to prevent overbrowning, cover top with foil for the last 5 to 10 minutes of baking. Cool slightly in pan on a wire rack.
Serve warm or cool completely. Cut into rectangles. Makes 25 servings.