Mike loves Key lime pie, but Key limes – smaller and more tart than Persian limes – are hard to come by in Pittsburgh. A few months back, I perused some recipes online, hoping to find that you can easily substitute Persian for Key limes in pies. You can, of course. But there are a host of people on the internet who are here to tell you with near fanatical devotion that it simply won’t be the same.
Maybe they’re proud Floridians, I don’t know. But nearly every lime pie post I read had an incredibly enthusiastic Key lime loyalist assuring readers that Key limes are more tart! Key limes are so much better! And don’t think of using bottled Key lime juice because it’s absolutely not the same! I was surprised to find this level of devotion to a citrus fruit…and that’s saying a lot given my undying love of lemons. In any case, my Persian limes worked very well in this tart, which Mike proclaimed as delicious. Next time, I’ll pre-bake the tart shell for longer to put more color on the pastry and ensure it’s done on the bottom.
For the pastry
- 1 1/2 cups flour
- 1/2 teaspoon salt
- 1/4 cup cold butter, cut into small pieces
- 1/4 cup shortening
- About 3-4 tablespoons ice water
For the filling
- 4 egg yolks
- 14-ounce can sweetened condensed milk
- zest from 1/2 lime
- 1/2 cup fresh lime juice (from about 4 Persian limes)
Preheat oven to 450 degrees. In a large bowl, combine flour and salt, then add butter and shortening. Cut butter and shortening into the flour until the mixture looks like coarse, pea-sized crumbs. Sprinkle 1 tablespoon of water over mixture and toss with a fork; repeat with remaining water, 1 tablespoon at a time, until the mixture comes together; you don’t want to use more than 1/4 to 1/3 cup of water total or your mixture will be too soggy. Gather dough into a ball and knead it gently to bring it together.
Roll pastry out between two pieces of parchment paper, then peel off the top sheet. Carefully flip the dough over into a 9-inch fluted tart pan with a removable bottom and position the pastry into the tart pan, then peel off the parchment. Gently press the pastry into the sides; I use a small bit of extra pastry for this to prevent it from tearing as it’s pressed into the fluted nooks.
At this point, you can trim the excess pastry if you like, but I chose to let my shell bake with the excess pastry hanging over the sides and trim it after it had baked to prevent shrinkage like they do on the Great British Baking Show. Prick the bottom of the shell with a fork. Line the shell with a double thickness of aluminum foil and bake for 8 minutes, then remove the foil and bake for another 8 minutes, until golden (mine was a bit pale, so next time I’ll bake it for another 10 minutes or so to start with). Remove from an oven and place on a wire rack to cool completely; if you’ve left your excess pastry on, you can trim it as soon as you take it out of the oven.
Lower your oven temperature to 350 degrees. In a medium bowl, whisk egg yolks, sweetened condensed milk, lime zest, and lime juice. Pour into cooled shell and bake for 15-20 minutes, until set. Cool at room temperature for 1 hour, then cover and chill for 2-3 hours before serving.
Makes 8 servings.