Preheat oven to 300 degrees F.

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 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, lemon juice, and 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 allow to cool to room temperature.

Fold beaten egg whites into lemon mixture, and then fold in whipped topping.

Spread lemon mixture into pie shell and cover with plastic wrap. Chill for several hours.

When ready to serve, whip whipping cream with powdered sugar and spread over the top of the pie. Garnish with lemon zest.