Preheat your oven to 350°F (175°C) to ensure the temperature is just right for baking your pie crust.

Roll out your pie crust dough and place it into a 9-inch pie pan, pressing it against the sides. Prick the bottom with a fork, cover with foil filled with rice or beans, and bake for 15 minutes. Remove the foil and continue baking for another 15-20 minutes until golden.

Combine ¾ cup sugar, 3 tablespoons cornstarch, and ¼ teaspoon salt in a saucepan. Gradually whisk in 1½ cups orange juice and cook over medium heat until thickened. Temper the egg yolks with a bit of hot mixture before stirring back into the saucepan with 1 tablespoon butter and 1 teaspoon orange zest.

In a double boiler, whisk together 4 egg whites and ½ cup sugar until the sugar dissolves and mixture reaches 160°F (70°C). Remove from heat and whip the egg whites until stiff peaks form and mixture cools.

Pour the hot orange curd filling into the pre-baked crust. Spread the fluffy meringue over the curd, sealing the edges to prevent shrinking.

Carefully toast the meringue using a kitchen torch until a light brown shade is achieved. Let the pie cool at room temperature for 1–2 hours before slicing.