In a medium mixing bowl, stir together 1-1/4 cup flour, mace, and salt. Using a pastry blender, cut in shortening until pieces are pea-size. Sprinkle 1 tablespoon of the water over part of the mixture; gently toss with a fork. Push moistened dough to the side of the bowl. Repeat moistening dough, using 1 tablespoon of the water at a time, until all the dough is moistened. Form dough into a ball. Roll dough into a 12-inch circle. Transfer to a 9-inch pie plate. Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry. Crimp edge; set aside.
Preheat oven to 350 degree F. For filling, in a bowl combine eggs, corn syrup, sugar, butter, molasses, and vanilla. Mix well. Stir in walnut pieces.
Place the pastry-lined pie plate on the oven rack. Carefully pour the filling into the pastry shell.
To prevent overbrowning, cover edge of pie with foil. Bake for 25 minutes. Remove foil. Bake for 20 to 25 minutes more or until a knife inserted near center comes out clean. Cool on a wire rack. Serve pie with ice cream. Refrigerate pie within 2 hours; cover for longer storage. Makes 10 to 12 servings.