Key Lime Squares

Key Lime Squares

Most cooks go to the market with a dish or recipe in mind. I do, too. But every now and then something catches our eye, and we have to buy it.  We find ourselves wondering what would go well with it and asking, “Should I cook this or that?”

That’s what happened with these key limes. This is Arizona, where we are hundreds of miles away from Florida, so finding key limes in our market was a pleasant surprise.

At first, I was going to bake a cake. Then the plan changed to a tart and just as I started to gather my ingredients, I grabbed my phone and found this lime recipe. After making a few changes, the final product turned out to be one of the tastiest bars ever! Instead of using regular limes, we used key limes and added old fashioned oats in place of the pistachio.

Important: If your squares seem too soft, put them in the fridge for at least an hour.  They will be much easier to cut later.




  • 4 tablespoons (½ stick) unsalted butter, melted and cooled, plus more for pan
  • ⅔ cup old fashioned oats
  • 1 cup (4 ounces) graham-cracker crumbs
  • ¼ cup sugar
  • 1 tablespoon grated key lime zest

Make the crust: Preheat oven to 350°. Brush an 8-inch square baking dish with melted butter. Line bottom with parchment, leaving a 2-inch overhang on two sides.

In a food processor, finely grind old fashioned oats with graham-cracker crumbs, sugar, and zest. Blend in butter. Press mixture into bottom and ½ inch up sides of prepared pan. Bake until lightly browned, 8 to 12 minutes. Let crust cool 30 minutes.

Meanwhile, make the filling (see below). Pour filling into cooled crust; carefully spread to edges.

Bake until set, about 15 minutes. Transfer pan to a wire rack to cool completely; chill 1 hour before removing from pan. Using parchment overhang, lift out of pan, and transfer to a cutting board. With a serrated knife, cut into 16 squares, wiping knife with a damp kitchen towel between each cut. Squares can be refrigerated in an airtight container up to 2 days.


Lime Square Filling

  • 2 large egg yolks
  • 1 can (14 ounces) sweetened condensed milk
  • ½ cup fresh key lime juice

In a large bowl, whisk together egg yolks and condensed milk. Add key lime juice; whisk until smooth.

Makes: 16

Key Lime Squares


Key Limes

Adapted from Martha Stewart’s Lime Squares with Pistachio Crust