- Let egg whites stand at room temperature for 30 minutes. Preheat oven to 450 degrees F.
- Prepare and bake Pecan Pastry Shell: Combine all-purpose flour and salt. Using a pastry blender, cut in shortening until pieces are pea-size. Stir in toasted pecans. Sprinkle 1 tablespoon cold water over part of flour mixture; gently toss with a fork. Push moistened dough to one side of the bowl. Repeat, using 1 tablespoon cold water at a time, until all of flour mixture is moistened. Form dough into a ball. On a lightly floured surface, slightly flatten dough. Roll dough from center to edge into a 12-inch circle. Transfer pastry to a 9-inch pie plate. Ease into pie plate, being careful not to stretch pastry. Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry. Crimp edge as desired. Do not prick pastry. Line with a double thickness of foil. Bake in a 450 degree F oven for 8 minutes. Remove foil. Bake 7 to 10 minutes more or until lightly golden; set aside. Reduce oven temperature to 350 degrees F.
- Meanwhile, for filling, in a medium saucepan combine the brown sugar, cornstarch, and salt. Stir in LACTAID® Reduced Fat Milk. Cook and stir over medium heat until thickened. Cook and stir for 2 minutes more. Remove from heat. Gradually stir about 1 cup of the hot filling into egg yolks, stirring constantly. Pour yolk mixture into remaining hot filling in saucepan. Bring to a gentle boil. Cook and stir 2 minutes more. Remove from heat. Stir in butter until melted. Stir in vanilla. Keep warm.
- For meringue, in a large mixing bowl combine egg whites and cream of tartar. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add the granulated sugar, 1 tablespoon at a time, beating on high speed until mixture forms stiff peaks (tips stand straight).
- Spoon hot filling into pastry shell. Immediately spread meringue evenly over hot filling, carefully sealing to edge of pastry to prevent shrinkage. Bake in a 350 degree F oven for 15 minutes. Cool on a wire rack 1 hour. Chill at least 3 hours or up to 6 hours before serving.