4 tsp lime zest, grated
1/2 cup lime juice
4 large egg yolks
14 oz sweetened condensed milk
11 graham crackers, 1.25 cups of crumbs
3 tbsp sugar
5 tbsp unsalted butter, melted
8 tbsp heavy cream, chilled
1/4 cup powdered sugar
Half of a lime sliced paper thin and dipped in sugar (optional)
Whisk zest and yolks in medium bowl until tinted green, about 2 minutes. Beat in milk, then juice; set aside at room temperature to thicken.
Combine graham cracker crumbs, sugar, and butter and press into a pie pan. Bake for 15 minutes, at 325 degrees. Cool 20 minutes.
Pour lime filling into crust.
Bake at 325 degrees 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. (Cover with a plastic wrap laid directly on filling.)
Whip the heavy cream with the powdered sugar. Pipe the whipped cream over the pie and garnish with sugared lime slices.