I don’t know whether this recipe is an entirely traditional key lime pie (I guess it can’t be if you’re using Tahitian Limes), but it’s still very tasty. If you want to be more true to tradition, find key limes (or Mexican limes), don’t add the beaten egg whites before cooking and reduce the cooking time to 15 – 18 minutes; that will give you a denser filling, but I find it a bit too sweet for my taste. This pie filling is lighter and some of the sweetness of the sweetened condensed milk is lifted by the whipped egg whites.
Key (or Tahitian) Lime Pie
4 tsp grated lime zest
1/2 c lime juice from 3 to 4 limes
5 large egg yolks
1 can sweetened condensed milk (395g/14oz)
3 large egg whites
Graham Cracker Crust
125g Graham Crackers/ Marie biscuits , processed to fine crumbs (1 1/4 cups)
3 tbsp sugar
5 tbsp unsalted butter , melted
Filling: Whisk zest and yolks in medium bowl for about 2 minutes, until pale green and ribbon consistency. Beat in the sweetened condensed milk, then the lime juice; set aside at room temperature and allow to thicken.
Crust: Adjust oven rack to center position and heat oven to 325°F/160°C. Mix the crumbs and sugar in medium bowl. Add butter and stir with fork until well blended. Spread the mixture into 9-inch pie pan and press over the bottom and up the sides of pan to form an even crust (or line a 9″ springform cake pan with parchment, and press evenly to the bottom of it). Bake for about 15 minutes, until lightly browned and fragrant. Transfer pan to wire rack, and allow to cool for about 20 minutes.
While the crust cools, whip egg whites to stiff peaks, then fold through the lime filling. Pour the mixture onto the cooled crust and bake about 20 minutes, until center is just set; it should still be slightly wobbly when jiggled. Return pie to wire rack; cool to room temperature. Refrigerate until well chilled (about 3 hours). It can also be covered with plastic wrap sprayed with oil, laid directly on the filling and refrigerated for up to 1 day.
Garnish with freshly whipped cream and slices of sugared lime.