Mom's Gone with the Wind Heavenly Pie

Adjust oven rack to middle position and heat oven to 300 degrees. Grease 9-inch deep-dish pie plate.

Using stand mixer fitted with whisk, whip egg whites, 1/2 teaspoon salt, and cream of tartar on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and whip whites to soft billowy mounds, 1 to 3 minutes. Gradually add 1 cup sugar and whip until glossy, stiff peaks form, 3 to 6 minutes.

Spread meringue into prepared pie plate and smooth into even layer. Run finger around inside edge of pie plate to create small gap between edge of meringue and rim of plate. Bake meringue until golden brown and set, about 1 hour. Turn off oven and let meringue dry completely for 3 hours longer. Let meringue cool completely on wire rack, about 30 minutes. (Meringue will crack and deflate after baking to form crust.)

Meanwhile, whisk remaining 1/2 cup sugar, egg yolks, lemon zest, lemon juice, and remaining 1/4 teaspoon salt together in medium saucepan until smooth. Cook over medium-low heat, stirring constantly, until mixture is thickened and registers 170 degrees, about 5 minutes. Strain curd through fine-mesh strainer into large bowl. Place plastic wrap directly on surface of curd. Refrigerate until completely cooled, about 1 hour.

Using stand mixer fitted with whisk, whip cream on medium-low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1 to 3 minutes.

Fold half of whipped cream into cooled lemon curd until no white streaks remain. Spread lemon mixture into cooled meringue shell and smooth into even layer. Spread remaining whipped cream over top and refrigerate until set, about 1 hour. Serve.