Using a food processor or a pastry blender, cut cold butter into flour and salt until the mixture resembles a coarse meal.

Pour cold water over the mixture and work it in by tossing with a fork until the dough begins to form.

Divide the dough into 2 balls, flatten them into rounds, wrap in plastic wrap, and refrigerate for a minimum of 20 minutes.

Roll the dough into a 12-inch round and place it in a 10-inch pie plate. Trim and flute the edges as desired.

Poke a few holes in the bottom of the pastry shell and refrigerate for an additional 20 minutes before baking at 400°F for 12–15 minutes.

Cool completely before adding the filling.

In a medium saucepan, combine corn starch, cake flour, sugar, and salt.

Pour in water and stir constantly over medium-low heat until the mixture comes to a slow boil.

Remove from heat and reduce flame to low.

Pour about a cup of the mixture onto the slightly beaten egg yolks while whisking constantly.

Pour the egg mixture back into the pot, whisking constantly and cook for an additional 3 minutes.

Remove from heat and stir in the lemon juice and lemon rind.

Whisk in the butter one tablespoon at a time.

Pour the filling into the baked and cooled shell.

Whip egg whites, vanilla, salt, and cream of tartar to soft peaks.

Gradually add sugar while continuing to beat the egg whites.

Dollop heaping tablespoons onto the pie and spread over the filling, ensuring the meringue touches the crust.

Bake in a 325°F oven for 20–25 minutes or until the meringue is well browned.

Cool pie thoroughly in the refrigerator before serving.

Use a sharp knife dipped in cold water to cut the pie into slices.