Traditionally, Key lime pie is made from Key limes, also known as Mexican or West Indian limes. They’re smaller and seedier than conventional limes, and their aromatic juice more sour. Combined with super-sweet condensed milk, egg yolks and a graham cracker crust, that juice makes a terrific pie.
These dessert bars are the traditional pie’s less fussy but equally irresistible buddy. Go ahead and use Key limes if you’ve got them, but the limes available in most grocery stores, called Persian or Tahitian limes, will work beautifully, too. They’re also considerably less work to juice. You’d need about a dozen Key limes to get the 3/4 cup of juice you need for these bars, whereas you’ll need only about six conventional limes. And — purists, avert your eyes — if you’re short on time, you can use bottled Key lime juice. Just check the ingredients before you buy: You want 100-percent juice without any added sugar.
For the crust, vanilla wafer cookies step in for the classic graham crackers. Either cookie would work just fine, but the vanilla in the cookies complements the floral notes of the lime juice nicely. To finish, the bars are topped with lightly sweetened whipped cream. The cream tames the lime’s acidity and is less finicky than meringue.
Super simple to make and travel friendly, these bars beg to be taken to your next (responsibly distant) picnic, no plates or silverware required. Cut them before you leave the house to make sharing easy, but bring the heavy cream and confectioners’ sugar, unwhipped, in a jar. (Keep both the jar and the bars chilled, if possible.) Just before serving, make a big show of shaking the jar to whip the cream and spoon it onto the individual squares. Then sit back and feign exhaustion while the praise rolls in. You’ll look like you’ve earned it.
