Step 1

Mix the flours, sugar, and salt in a medium bowl. Cut butter into ½-inch cubes, then add them to the bowl with flour. Smash each cube of butter with your fingers, then knead just until the dough is formed. Shape into a ball and check the dough temperature. If not between 18 and 21°C, refrigerate until at the desired temperature.

Step 2

Place the dough on a lightly floured working surface, then roll it out to a circle 14 inches in diameter. Line a pie plate with the dough, then crimp the edges as desired. Wrap the pie in cling film, and refrigerate anywhere from two hours to overnight.

Step 3

Set the oven to preheat to 177°C and position the oven rack in the lower-middle part of the oven. Place a large sheet of aluminum foil on top of the pie, then press into the pie crust, so that the insides of pie crust are completely lined with aluminum foil. Pour the sugar into the pie crust, filling it out completely.

Step 4

Put the pie crust on a larger baking tray, then put it in the oven and bake for 60-75 minutes, until completely set and golden around the edges. Gather the foil and take the sugar out. (Place the sugar in a heatproof bowl, and use it in other recipes.).

Step 5

To make the filling, first, mix sugar, cornstarch, and salt in a 3-quart saucepan. Next, whisk in the eggs, lime zest, lime juice, and milk. Cook over medium-low heat for 5 minutes, whisking constantly. Then, increase the heat to medium, and continue whisking for the next three minutes until thick. Once bubbly, while still constantly whisking, cook for exactly two more minutes (set a timer!). Take off heat and stir in rosewater, if desired. Pour into the pie crust.

Step 6

To make the meringue, combine egg whites, sugar, salt, cream of tartar, and vanilla seeds in a large bowl. Set the bowl over steaming water, and mix with a spatula for 8-10 minutes, until the mixture is at a constant 79°C temperature. Then, whisk with a hand mixer at high speed for 5 minutes, until glossy and stiff.

Step 7

Set the oven to preheat to 190°C and position the oven rack in the lower-middle part of the oven.

Step 8

Spoon the meringue into a piping bag fitted with a large star nozzle. Cover the custard completely with meringue kisses. Alternatively, you can simply just spread the meringue with the back of a spoon.

Step 9

Bake for 15 minutes, until the meringue is well browned. Take out of the oven and wait until the pie comes to room temperature before you wrap it loosely in plastic and refrigerate it. For serving, the pie temperature should be at 16°C.