Old-fashioned Butterscotch Pie

FOR FILLING: Prepare and fully bake pastry shell as directed; set aside to cool. In a heavy, medium saucepan stir together the brown sugar, flour, and salt. Add egg yolks and milk. Cook while stirring with a wire whisk till thickened and bubbly. (Mixture may appear curdled. Stir briskly while cooking and mixture will become smooth.) Cook and stir 2 minutes more. Remove from heat. Stir in margarine or butter and vanilla. Pour hot filling into baked pastry shell.

FOR MERINGUE: In a mixing bowl beat egg whites and cream of tartar with an electric mixer on medium speed about 1 minute, or till soft peaks form (tips curl). Gradually add sugar, 1 tablespoon at a time, beating on high speed about 4 minutes more, or till mixture forms stiff, glossy peaks (tips stand straight) and sugar completely dissolves. Immediately spread meringue over hot filling, spreading to edge of pastry to seal and prevent shrinkage.

Bake pie in a preheated 350 degrees oven for 15 minutes. Cool on a rack for 1 hour. Chill 3-6 hours before serving. Store in the refrigerator.