I made this last week and since it was for a special occasion I went through the trouble of finding real key limes. It took about 9 of these golf ball-sized suckers to get 2/3 cup of juice. I used a recipe from Saveur Magazine that is based on the one served at Joe's Stone Crab in Miami.
I liked the pie – the custard should have been thicker, but I think I ended up using a little more than the 2/3 cup of juice – after all that work juicing them I wasn't going to waste any. I probably used too much zest for the same reason, so there was a touch of bitterness from the pith. The flavor of the custard was bright, tart and refreshing.
I thought the crust was great, I liked the flavor and it had great texture. I only used half the sugar in the recipe.
1 cup plus 2 1/2 tbsp. graham cracker crumbs
1/3 cup sugar
5 tbsp. unsalted butter, melted
1 1/2 tbsp. lime zest (from 2 limes)
3 egg yolks
1 14-oz. can sweetened condensed milk
2/3 cup fresh Key lime juice
1 cup heavy cream, chilled
1 tbsp. confectioners' sugar
1. Heat oven to 350°. Pulse cracker crumbs, sugar, and butter in a food processor to combine. Press into bottom and sides of a 9" pie pan. Bake until lightly browned, about 10 minutes. Let cool.
2. In a medium bowl, beat lime zest and egg yolks with a hand mixer until pale and thick, 5 minutes. Add milk and beat until thickened, 3–4 minutes more. Add lime juice; mix until smooth. Pour filling into pie crust; bake until filling is just set in the middle, 8–10 minutes. Let cool. In a medium bowl, whisk cream and confectioners' sugar to stiff peaks. Spread whipped cream over top of pie and chill 2–3 hours before serving.