Grease a 9” glass pie plate (or spray with cooking spray).
In large bowl, beat 4 egg whites with cream of tartar until stiff, but not dry. Add 1 cup sugar slowly until stiff and glossy.
Spread meringue in pie plate, making a “well” in the center for the filling.
Bake at 300 degrees for 1 hour. Turn off the heat and leave crust in oven for at least one hour or, preferably, overnight.
In small, heavy saucepan, whisk together egg yolks, POM-Cranberry juice, lemon juice and 1/3 cup sugar. Heat over medium-low heat until mixture thickens and starts to bubble. Remove from heat and transfer to a large bowl. Cover with plastic wrap and bring to room temperature.
Fold whipped topping into POM mixture; add a few drops of red food coloring, if desired. Spread into pie shell and cover with plastic wrap. Chill for several hours.
When ready to serve, whip whipping cream with vanilla and powdered sugar and spread over the top of the pie. Garnish with fresh pomegranate arils if available.