Preheat oven to 375°F.
In a large bowl, place flour, salt, and sugar, stir to combine. Create a well in the center of the flour and add the oil. Using a fork or your hands, slowly begin to incorporate the flour and oil, creating a crumbly mixture. Add milk, a tablespoon at a time, and begin working the dough into a ball (the dough should resemble sugar cookie dough, not quite like traditional pie dough).
Sprinkle a little flour on a clean work surface and roll the dough into a large circle (large enough to fit your pie pan with about 1 inch of overhang). Transfer the dough to the pie pan, pinch dough into the pan’s piped edges, and trim off any excess.Place a sheet of parchment over the dough and weigh down with pie weights or dried beans. Place in the oven and bake for 15-20 minutes or until the crust is lightly golden. Remove from the oven and set aside.
In a medium saucepan, combine lemon juice, zest, eggs, egg yolks, and sugar, whisk to combine. Slowly heat the mixture over low heat, whisking consistently, until warmed through. Slowly begin adding butter, a tablespoon at a time, until melted and smooth. Filling will begin to thicken after each pat of butter is added. Once thick, remove from the heat and pour into your pie crust.
Return the pie to the oven and bake for 10-15 minutes or until the filling has set, remove from the oven and set aside.
In a stand mixer fitted with a whisk attachment, combine egg whites, cream of tartar, sugar, and vanilla extract. Whisk on low, gradually increasing the speed, until stiff peaks form. Spoon meringue on top of the pie, return to the oven, and bake for 10 minutes or until meringue turns golden brown. Remove from the oven and set aside to cool completely before slicing and serving.