1/2cuplemon juicefreshly squeezed, about 3-4 lemons
a pinch of salt
Preheat the oven to 400F. Using an 8x8 inch pan, roll out the pie crust and cut to fit the bottom of the dish. Cut to be slightly bigger than the bottom since it will shrink as it cooks. Spray the 8x8 pan with non-stick spray and lay the pie crust dough into the bottom.
Into a 2 quart saucepan add the cornstarch, sugar, and salt. Give a quick whisk. Whisk the warm water, lemon juice, and zest into the saucepan. Turn the burner on medium-low. Stir until the mixture begins to boil. Remove from the heat.
In a small bowl, whisk the egg yolks. One Tablespoon at a time, drizzle five Tablespoons of the cornstarch mixture into the egg yolks, whisking to avoid clumping.
Next drizzle the warmed egg yolk mixture into the saucepan with the cornstarch to fully temper. Return to heat and whisk until thick, without boiling, for about 10 minutes. Add the butter and stir until melted.
Pour the lemon mixture over the unbaked pie crust.
Make the Meringue Topping
In a large bowl or stand mixture, add the egg whites and pinch of salt. Beat on high speed until soft white peaks form.
Keeping the speed on high, slowly add in sugar 1 Tablespoon at a time until all sugar is incorporated. Keep beating until stiff white peaks have formed. This will look similar to the texture of marshmallow fluff, will be glossy, and pull from the bowl during beating in a ribbon-like form. Removing the beater from the bowl should show the meringue holding form in a stiff peak.
Spoon out the meringue topping onto the still warm filling. Use the back of a spoon or a rubber spatula to pat the meringue making the traditional peaks of a lemon meringue.
Bake at 400F for 10-15 minutes on the center wrack. Remove from the oven when the meringue is set and browning on the tips.
Allow to cool at room temperature for 1 hour, refrigerate and allow to chill for 4-8 hours before serving.
These pie bars can be stored in the refrigerator in an air tighter container for up to 3 days.