MAKE THE CRUST

1. Preheat oven to 300 degrees. Butter the bottom and sides of a 9-inch deep pie dish.
2. Place the egg whites and cream of tartar in the mixing bowl of a stand mixer fitted with the whisk attachment. Whisk the egg whites and cream of tartar on medium-high until frothy, about 30 seconds. Whisk in one cup of the sugar about 1/3 at a time, incorporating each time before adding more. Whisk on high until the egg whites become stiff and shiny but not dry. See my tip above.
3. Transfer the beaten egg whites to the pie dish, spreading them evenly across the bottom and also up the sides. Spread up to the top edge of the rim but no higher, unless you don’t care about it rising above the edge, because it will rise up. Use the back of a spoon to make fancy swirls along the edge if you prefer. I was lazy.
4. Bake the meringue crust for about 45 to 50 minutes until it’s puffed up and just barely starting to brown. It will have some cracks in it but that’s normal. DON’T OPEN THE OVEN DOOR! This is one meringue that will crack on its own even if you don’t open the door. However, if you don’t want excessive cracks, allow the crust to cool in the turned off oven, door closed, until it’s completely cool. If you don’t care about the excess cracks you can ignore this step. This pie isn’t the prettiest pie anyway to be honest, but it sure makes up for it in taste.

COOK THE LEMON CURD FILLING

1. While the crust is baking, make the lemon curd filling.  Add the egg yolks and the remaining 1/2 cup of  sugar to a small saucepan, (one that fits in the top of a bigger saucepan, to make a double boiler). Whisk the egg yolks and sugar until smooth and thick. Add the lemon juice and 1 tablespoon of the zest, and place the pan over a pan that’s about 1/4 full of boiling water. Adjust heat to medium. Cook the mixture, stirring constantly, until the mixture has thickened enough to coat the back of a spoon without running or dripping off. This could take 8 to 10 minutes. Place the filling in a refrigerator until it’s chilled. 
2. MICROWAVE OPTION: Add the ingredients to a microwave safe bowl and whisk to combine. Microwave for for about 4 to 5 minutes, stopping after each minute to whisk until smooth again. After about 3 minutes, I stop and check it every 45 seconds. Once it’s thick enough to coat the back of a spoon it’s ready. Refrigerate until chilled.

WHIP THE WHIPPING CREAM AND MIX WITH THE LEMON CURD FILLING

1. Add the heavy whipping cream, powdered sugar, vanilla and the remaining 2 teaspoons of zest to the bowl of a stand mixer fitted with the whisk attachment. Place an old kitchen towel over the top of the mixer (trust me on this). Beat on high until the whipping cream becomes thick. Transfer roughly 1/2 of the whipping cream to a small bowl and set aside.
2. Add the cooled lemon curd filling to the bowl of remaining whipped cream, Beat on medium speed for about 30 seconds to combine. Transfer the lemon filling to the meringue crust, spreading it evenly to the edges.
3. Refrigerate pie until the filling has a few minutes to set, then spread or dollop the remaining whipped cream on the top of the filling. Keep the pie refrigerated for 4 to 5 hours or overnight.
4. Optional: Sprinkle lemon zest over the whipped cream or place small pieces of lemon slices or lemon rind on the top.
5. The pie will keep for a couple days in the fridge before the whipped cream starts to break down.