Thank me later - as long as she likes it to actually taste like lime. From America's Test Kitchen. Squeeze fresh limes - don't use bottled lime juice. Don't shorten the "Setting/cooling" time.
GATHER YOUR INGREDIENTS
Lime Filling
4 teaspoons grated lime zest
1/2 cup lime juice from 3 to 4 limes
4 large egg yolks
1 (14-ounce) can sweetened condensed milk
Graham Cracker Crust
11 graham crackers, processed to fine crumbs (1 1/4 cups)
3 tablespoons granulated sugar
5 tablespoons unsalted butter, melted
Whipped Cream Topping
3/4 cup heavy cream
1/4 cup confectioners' sugar
INSTRUCTIONS
1. FOR THE FILLING: Whisk zest and yolks in medium bowl until tinted light green, about 2 minutes. Beat in milk, then juice; set aside at room temperature to thicken.
2. FOR THE CRUST: Adjust oven rack to center position and heat oven to 325 degrees. Mix crumbs and sugar in medium bowl. Add butter; stir with fork until well blended. Pour mixture into 9-inch pie pan; press crumbs over bottom and up sides of pan to form even crust. Bake until lightly browned and fragrant, about 15 minutes. Transfer pan to wire rack; cool to room temperature, about 20 minutes.
3. Pour lime filling into crust; bake until center is set, yet wiggly when jiggled, 15 to 17 minutes. Return pie to wire rack; cool to room temperature. Refrigerate until well chilled, at least 3 hours. (Can be covered with lightly oiled or oil-sprayed plastic wrap laid directly on filling and refrigerated up to 1 day.)
FOR THE WHIPPED CREAM: Up to 2 hours before serving, whip cream in medium bowl to very soft peaks. Adding confectioners' sugar 1 tablespoon at a time, continue whipping to just-stiff peaks. Decoratively pipe whipped cream over filling or spread evenly with rubber spatula. Garnish with optional sugared lime slices and serve.