1️⃣ Prepare the Meringue Crust:
Preheat the oven to 275°F (135°C). Grease a 9-inch pie pan and set aside.
In a clean mixing bowl, beat egg whites with cream of tartar on medium speed until soft peaks form.
Gradually add 3/4 cup sugar, one tablespoon at a time, while beating on high speed until stiff and glossy peaks form.
Fold in vanilla extract and cornstarch gently.
Spoon the meringue into the prepared pie pan, shaping it into a crust with slightly raised edges.
Bake for 50–60 minutes, or until firm and lightly golden. Turn off the oven and cool the crust inside with the door ajar.

2️⃣ Make the Lemon Filling:
In a medium saucepan, whisk egg yolks, remaining 1/4 cup sugar, lemon juice, and lemon zest.
Cook over medium-low heat, stirring constantly, until thick enough to coat the back of a spoon (about 5–7 minutes). Avoid boiling.
Strain the mixture through a fine-mesh sieve to remove any cooked egg bits. Cool to room temperature.
In a separate bowl, whip heavy cream to stiff peaks. Gently fold whipped cream into the cooled lemon mixture until smooth.

3️⃣ Assemble the Pie:
Pour the lemon filling into the cooled meringue crust and spread evenly.
Refrigerate for at least 3–4 hours, or until fully set.

4️⃣ Garnish and Serve:
Top with whipped cream and garnish with lemon zest curls, if desired.
Slice and serve chilled.