Boy, do I love me some Key Lime Pie! I always have, as far back as I can remember. It may just be the only type of dessert that can sway me, at a restaurant, from ordering a chocolatey confection. And that is no small feat! I just love the puckery tang, the sweet, crumby graham cracker crust, and the perfect fluff of browned meringue on top.
So imagine my delight when I happened to stumble across a big package of fresh key limes in my local international foods market last weekend! I don't know if I've ever truly realized that key limes are so much tinier than regular Persian limes. I got about 2 lbs. of key limes for under 2 bucks, which I believe is a fair price although I wouldn't really know. It seemed good! I was eager to test them out. I've never made a from-scratch Key Lime Pie before, let alone with authentic key limes. But I set out to change that.
I debated for a bit about what type of crust I should do, and what type of topping I should do. I love the graham cracker crust, but I've also had Key Lime Pies with a more standard, not-too-sweet pie dough that I think is really good. I also considered a fresh whipped cream topping on this. In the end, the graham cracker/meringue combo won. I wasn't disappointed; it was a good choice!
One minor note I thought I would mention: it's very important to chill the finished pie after about an hour of cooling on the counter. I learned this the hard way! We had to leave the house right after this came out of the oven, and we didn't get back for about 4-5 hours. When we arrived home, the meringue had shriveled up and pulled away from the sides of the pan! It still tasted awesome, it just didn't look nearly as pretty as it did when it first came out of the oven (and fortunately many of my pictures were taken while it was still attractive!). So if you're serving this to company or just want your pie to remain beautiful, chill it for several hours before you enjoy it.
Key Lime Pie
adapted from United Cakes of America
makes one 9-inch pie
Nonstick cooking spray
10 full sheets (5 oz.) graham crackers
4 Tbsp. unsalted butter, melted
6 Tbsp. granulated sugar, divided
1 (14-oz.) can fat-free sweetened condensed milk
3 eggs, yolks and whites separated (whites at room temperature)
2/3 cup fresh key lime juice
1/8 tsp. cream of tartar
1. Preheat oven to 300 degrees F. Using a food processor or a Ziploc bag and a rolling pin, crush the graham crackers until they are fine crumbs. Add 2 Tbsp. granulated sugar and the melted butter to the graham crackers, tossing to coat crumbs with butter.
2. Line a 9-inch round cake pan with parchment paper, spraying the pan with nonstick cooking spray both under and on top of the parchment. Press the graham cracker mixture into the prepared pan, making sure it is even. Bake on the center rack in the oven for 8-10 minutes, or until lightly browned and fragrant. Set on a rack to cool.
3. Make the filling by whisking the egg yolks until well combined. Add in the condensed milk slowly, whisking the whole time. Slowly drizzle in the lime juice; the mixture will thicken as you whisk it. Pour the filling into the cooled pie crust.
4. Return the pie pan to the oven, and bake for about 20 minutes, or until the filling is just set and no longer jiggly. Remove the pan from the oven, return it to the rack, and allow it to cool.
5. Make the meringue by setting the egg whites and the cream of tartar in the bowl of a standing mixer fitted with the whisk attachment. Whisk the whites at a medium speed until they form soft peaks. Slowly add the remaining 4 Tbsp. sugar, one Tbsp. at a time, and continue whisking the whites at medium-high speed. Once the whites have formed stiff peaks, stop the mixer.
6. Crank up the oven to 400 degrees F. Spread the meringue onto the cooled pie, ensuring the entire surface is covered and the meringue seals the edges. If desired, fluff the meringue into little peaks or other designs on top. Return the pie to the oven and bake for an additional 5-6 minutes, just until the meringue is browned on top, making sure not to over-brown. Allow the pie to cool at room temperature for about 1 hour, then put it in the refrigerator for at least another 3 hours before serving.