Set the oven temperature to 375°F (190°C). Roll out chilled pie dough and line a 9-inch pie dish.

Blind bake crust with parchment and weights for 10 minutes.

Remove weights, then bake until edges are golden and the center is lightly golden for about 10-12 more minutes.

Cool crust to room temperature.

Set the oven to 350°F.

Whisk egg yolks.

In a saucepan, combine the lemon zest, juice, salt, cornstarch, sugar, and water. Cook over medium heat until thick.

Temper yolks with hot lemon mixture, then add back to the saucepan. Cook until thick and bubbly.

Turn off the heat, then add butter. Spread filling in the crust.

Beat egg whites with cream of tartar to form soft peaks. Gradually add sugar; beat to stiff peaks.

Spread meringue over filling, sealing edges to crust.

Bake on the lowest oven rack for 25 minutes.

Cool on a wire rack for 1 hour, then chill for 4 hours before serving.