Butterscotch Pie

1 can sweetened condensed milk
1 1/2 cups butterscotch morsels
1 cup granulated sugar, divided
3 tablespoons cornstarch
3 eggs, separated
1 baked pie shell

Combine milk with 2/3 can water in a saucepan. Heat to simmer. Add butterscotch morsels. Stir until melted. Add 2/3 cup sugar and cornstarch to egg yolks in a bowl. Beat well. Stir a small amount of hot mixture into egg yolks. Stir egg yolks into the hot mixture. Continue cooking, stirring until thickened. Pour into pie shell. Beat egg whites until soft peaks form. Add remaining sugar gradually, beating until stiff. Cover pie mixture. Seal edges. Bake at 350 degrees F for 25 minutes.