Preheat the oven to 350°F. Lightly brush or spray a 9-inch pie pan with oil. Crumble the pie crust into the pie pan, then press the crumbs firmly into the pan.

Finely zest 1 lemon. Squeeze the juice from the lemons until you have ½ cup plus 1½ teaspoons.

Whisk together ½ cup lemon juice, the lemon zest, sweetened condensed milk, and egg yolks. Pour into the prepared pie crust.

Beat the egg whites with 1½ teaspoons lemon juice on high speed until foamy. Add the powdered sugar, about 1 tablespoon at a time. Beat until stiff peaks form.

Spread the meringue over the pie, making sure to seal the edges of the crust. Bake for 15-20 minutes or until the top begins to brown. Let cool, then refrigerate for at least 2 hours or up to 1 day ahead.