Save two tablespoons of orange juice concentrate from the can for the meringue.
Put remaining juice concentrate in a saucepan and add 1 can of water and butter.
Bring to a boil.
Meanwhile blend 2/3 cup sugar, cornstarch, egg yolks, and 1 can of water until smooth.
Slowly stir the egg yolk mix into the boiling liquid. Bring to a boil again and cook 2 or 3 minutes, stirring constantly, until smooth and thick.
Pour into the pie shell. Cool.
Just before serving, make the meringue.
Assemble a double boiler. Into the top, place: egg whites, the 2 tablespoons of orange juice concentrate that you saved, salt, and 1/3 cup sugar.
Beat the egg white mixture at high speed over boiling water for 2 minutes. Then remove from heat and beat 2 or 3 minutes longer or until the mixture forms soft peaks.
Spoon the Orange Blossom Meringue in mounds around the edge of the pie. Place in the oven under the broiler until the meringue is a deep golden brown, about 1 minute. Watch carefully so you don't burn it. Serve within an hour or two.