Preheat oven to 425 degrees F. Prepare Flaky Pecan Pastry. On a lightly floured surface, slightly flatten dough. Roll dough from center to edge into a 12-inch circle. Wrap pastry circle around rolling pin; unroll into a 9-inch pie plate. Ease pastry into pie plate without stretching it. Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry even with edge of plate. Crimp edge as desired. Do not prick pastry. Line pastry with a double thickness of foil. Bake in the preheated oven for 12 minutes. Remove foil. Bake for 8 to 10 minutes more or until pastry is golden brown. Cool on a wire rack. Reduce oven temperature to 350 degrees F.
For filling, in a medium saucepan, combine brown sugar, cornstarch, and salt. Whisk in about 1/2 cup of the evaporated milk. Whisk in egg yolks until combined. Whisk in the remaining evaporated milk and the milk. Cook and stir over medium heat until thickened and bubbly. Remove from heat. Stir in butter and vanilla. Cover and keep warm. Prepare Meringue for Pie.
Pour warm filling into pastry shell. Gently spread meringue over warm filling, sealing to edge of pie. Bake for 15 minutes. Cool on a wire rack for 1 hour. Chill for 3 to 6 hours before serving; cover for longer storage. Makes 8 servings.
Flaky Pecan Pastry
In a medium bowl, stir together flour and salt. Using a pastry blender, cut in shortening and butter, cut up, until pieces are pea size. Stir in pecans. In a small bowl, combine 2 tablespoons ice water and 2 teaspoons vinegar. Sprinkle mixture over part of the flour mixture; toss gently with a fork. Push moistened dough to side of bowl. Repeat with 2 tablespoons additional ice water until all of the flour mixture is moistened. Gather mixture into a ball, kneading gently until it holds together. If necessary, cover and chill about 1 hour or until easy to handle.
Meringue for Pie
In a small bowl, sugar and brown sugar; set aside. In a large bowl, combine egg whites and cream of tartar. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add sugar mixture, 2 tablespoons at a time, beating on high speed until stiff peaks form (tips stand straight).