Prepare the Meringue Crust:

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

2. Make the Lemon Filling:

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

3. Assemble the Pie:

1. Pour the lemon filling into the cooled meringue crust and spread it evenly.
2. Refrigerate the pie for at least 3–4 hours, or until fully set.

4. Garnish and Serve:

1. Top the pie with whipped cream and garnish with lemon zest curls, if desired.
2. Slice and serve chilled.