In a medium bowl, mix together flour and 1/2 teaspoon salt. Using a pastry blender or two knives, cut half of the shortening into flour mixture, until fine crumbs form. Cut in remaining shortening until coarse crumbs form. Add water, 1 tablespoon at a time, tossing with fork until a dough forms. Shape dough into a disk and wrap in plastic wrap; chill for 30 minutes.
Preheat oven to 350 degrees F (175 degrees C).
On a floured surface, using a floured rolling pin, roll dough into an 11-inch circle. Fit dough into a 9-in quiche dish. Trim edges
In a heavy skillet, melt 2 tablespoons butter over low heat. Add nuts and stir for about 5 minutes, or until nuts begin to color. Let cool for 10 minutes.
Mix together beaten egg, maple syrup, sugar, 1/3 cup melted butter, vanilla, and 1/2 teaspoon salt. Stir in nuts. Pour filling into crust. Bake for 45 to 50 minutes, or until filling is set. Transfer pan to wire rack and cool.
