Some of my best summer dessert memories involve key lime pie. I just love the stuff. Normally, I'll go for the decadent, chocolatey desserts when given a choice. But key lime is one of the few fruity flavors I can never pass up. And to me, the pairing of tart, creamy key lime pie filling and a graham cracker crust is darn near perfect.
I wanted to provide something sweet for a potluck lunch Andy was having at work. I needed it to be something I could whip together quickly and easily. I bought way too many limes last week (though, sadly, they were not key limes) and inspiration hit me. A key lime pie bar! That would fit the bill wonderfully! I remembered that Martha Stewart's Cookies book had a bar cookie recipe that I wanted an excuse to make. Now was my chance.
I was very grateful for the ease of this recipe. The hardest part was separating the three eggs; I messed up and added an egg white to my already separated egg yolks. Oops! And the yolks already had the fresh lime zest added to it; double oops! So I had to toss the bowl of yolks and zest and start over again. Besides that little hiccup in the works, everything was smooth sailing. A quick graham cracker crust is baked, then cooled. Next, you pour a mixture of egg yolks, lime zest, sweetened condensed milk, and fresh lime juice on top of the crust and put the whole thing back into the oven. It bakes for another 10 minutes, and then it is cooled and chilled in the refrigerator. After that, you're ready to cut and serve!
We cut ours into 24 bars, even though Martha says you can cut 18 bars. The 24 bars seemed like they were a good size for a potluck, whereas the 18 bars would probably be better for a situation where you were only serving the bars for dessert after a dinner or something. Martha's bars were garnished with some freshly whipped cream and thin lime slices, but we just served ours plain. They were a hit at the lunch just the way they were, but I would like to serve them by the book next time; they'll be a bit prettier that way!
Key Lime Bars (or just plain Lime Bars!)
adapted from Martha Stewart's Cookies
makes 18-24 bars, depending on the size of your slices
For the crust:
1 cup plus 2 1/2 Tbsp. finely ground graham cracker crumbs
1/3 cup sugar
5 Tbsp. unsalted butter, melted
For the filling:
3 large egg yolks
1 1/2 tsp. finely grated lime zest
1 (14-ounce) can sweetened condensed milk
2/3 cup fresh Key lime juice (I used regular limes, about 4)
For the garnish:
1/4 cup heavy cream
2 Key limes, thinly sliced into half-moons
For the crust: 1. Preheat oven to 350 degrees F. Stir together graham cracker crumbs, sugar, and butter in a small bowl. Press evenly onto bottom of an 8-inch square glass baking pan. (I don't have a glass square baking pan, so I used a foil-lined metal baking pan, and it was fine.) Bake until dry and golden brown, about 10 minutes. Let cool completely on a wire rack.
For the filling: 1. Put egg yolks and lime zest in the bowl of an electric mixer fitted with the whisk attachment. Mix on high speed until very thick, about 5 minutes. Reduce speed to medium. Add condensed milk in a slow, steady stream, mixing constantly. Raise speed to high; mix until thick, about 3 minutes. Reduce speed to low. Add lime juice; mix until just combined.
Assemble bars: 1. Spread filling evenly over crust using a spatula. Bake, rotating halfway through, until filling is just set, about 10 minutes. Let cool completely on a wire rack. Refrigerate at least 4 hours or overnight.
Make garnish: 1. Cut 18 or 24 lime bars. Put cream in the clean bowl of an electric mixer fitted with the clean whisk attachment. Mix on medium-high speed until stiff peaks form. Garnish bars with whipped cream and a slice of lime. Ungarnished bars can be refrigerated in an airtight container up to 3 days.