Step 1

Getting Ready: In a 9-inch glass pie dish, prepare and blind-bake the whole wheat pie crust according to the directions in the recipe. This can be done up to a week in advance; crust can be held at room temperature if wrapped tightly in plastic.

Step 2

For the Filling: In a 3-quart stainless steel saucier, combine sugar, cornstarch, and salt and mix until smooth, then whisk in eggs, lime zest, and lime juice, followed by milk. Cook over medium-low heat, whisking constantly but gently, until hot to the touch, about 5 minutes.

Step 3

Increase heat to medium and continue whisking until thick, about 3 minutes longer. When custard begins to bubble, set a timer and continue whisking for exactly 2 minutes. (This is important to neutralize a starch-dissolving protein found in egg yolks.) Remove from heat and stir in rosewater, if using. Pour into prepared pie crust. For a silkier texture, first strain through a stainless steel sieve, pushing the thick custard through with a flexible spatula.

Step 4

For the Topping: Adjust oven rack to lower-middle position and preheat to 375°F (190°C). Prepare Swiss Meringue as directed, making a half or full batch depending on your own personal preference for meringue. Transfer to a piping bag fitted with a large star tip. Starting at the very edge of the pie, pipe meringue kisses over surface of custard until completely covered. Alternatively, spread meringue over custard with the back of a spoon. Place on a wire rack set inside a half sheet pan (this setup minimizes heat transfer to the custard) and bake pie until meringue is well browned, about 15 minutes.

Step 5

To Serve: Cool pie to room temperature, then cover loosely in plastic and refrigerate until no warmer than 60°F (16°C), about 3 1/2 hours. Cut with a wet chef's knife, rinsing the blade clean with cold water between slices. Wrapped in plastic, leftovers can be refrigerated up to 1 week.