Cook pie shell first.

Mix sugar and flour really good.

Beat egg yolks, add some milk (you'll use total of 2 1/2 cups for 1 pie, and 5 cups for 2 pies). Continue to beat and pour in rest of milk.

On stove, heat eggs, milk, flour, sugar mixture on medium high until it thickens, boil 2 minutes, take off heat, then add vanilla and butter. Stir until butter melts. Pour into pie crust.

Beat egg whites until stiff, add 1/3 cup sugar and 1/2 tsp vanilla. Beat well. Spread on top of pudding mixture. Bake on 350°F until browned, about 15 minutes.