In a stand mixer with a whisk attachment, or egg beater in a large metal mixing bowl, beat egg whites until white and fluffy, 5-6 minutes.
Slowly add 1 cup white sugar and cream of tartar. Beat egg white until it reaches a stiff peak and is glossy.
Pour meringue into a buttered 9 inch deep-dish pie plate. Using the back of a wooden spoon or spatula, pull the meringue up the sides of the pie plate so it looks like a crust and will hold the filling after being baked.
Bake Lemon Angel Pie crust meringue at 300F for 45-60 minutes depending on the temperature of your oven.
Once the pie crust is fully cooked, turn the oven off and leave the door ajar. Let the pie crust cool to room temperature before removing. This slow cooling down process ensures the meringue does not crack from a sudden change in temperature.
Meanwhile, beat 4 egg yolks in the top of a double boiler. Stir in 1/2 cup sugar, lemon juice and 1 tablespoon of lemon zest.
Whisk lemon curd over double boiler until cooked into a thickened sauce, approximately 4-5 minutes. Cover curd with saran wrap and rest at room temperature in your kitchen. Do not place lemon curd in the fridge as it will get hard and make it challenging to incorporate into the whipped cream later.
In a stand mixer with a whisk attachment, or egg beater in a large metal mixing bowl, whip whipping cream with vanilla until stiff.
Gently fold lemon curd into half of the whipped cream.
Pour lemon curd mixture into meringue pie shell. Top with remaining whipped cream. Sprinkle with lemon zest. Chill in the fridge until ready to serve.