Key Lime Pie

From Cooks Illustrated, Published March 1, 1997.

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

• 8 graham crackers , processed to fine crumbs 
• 3 tablespoons granulated sugar
• 4 tablespoons unsalted butter , melted

Whipped Cream Topping, optional

• 3/4 cup heavy cream
• 1/4 cup confectioners' sugar
• 1/2 lime , sliced paper thin and dipped in sugar (optional)

INSTRUCTIONS
1. For the Filling: Whisk zest and yolks in medium bowl until tinted light green, about 2 minutes. Beat in milk until smooth, then add lime juice.  Cover and set aside at room temperature to thicken about 30 minutes.

2. For the Crust: Adjust oven rack to center position and heat oven to 325 degrees. Process graham crackers in a food processor until fine, even crumbs (about 30 seconds).  Sprinkle the sugar and butter over the crumbs and pulse to incorporate. 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 12-15 minutes. Transfer pan to wire rack.

3. With the crust still warm, pour the thickened lime filling into crust; bake until center is set, yet wiggly when jiggled, 15 to 20 minutes. Return pie to wire rack; cool to room temperature about an hour. 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.)

4. For the optional 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.