I juiced the limes using my Mexican-style lime squeezer, which worked really well to extract a lot of juice, The only problem was that the seeds are pretty small, so some of them snuck through the holes of the squeezer. No big deal, since I noticed one or two. I strained the juice before it went into the pie and there were a lot more seeds than I noticed. So that's something to consider when you make this.
Also, the finished pie is more yellow than green. While I usually don't add coloring to foods, if you want this to be green, then a drop or two of food coloring is probably the only way you'll get that color.
Taste-wise, though, this was a really nice pie. A lot of lime flavor, good tartness, and enough sweet. I'd suggest a whipped cream garnish to finish it off.
Key Lime Pie
Adapted from Mrs. Rowe's Little Book of Southern Pies by Mollie Cox Bryan
1 1/2 cups fine graham cracker crumbs
1/4 cup sugar
6 tablespoons unsalted butter, melted
For the filling:
4 egg yolks
1 rounded teaspoon grated lime zest
1 (14-ounce can) sweetened condensed milk
1/2 cup freshly squeezed lime juice
First, make the crust.
Preheat the oven to 350 degrees.
Put the crumbs in a small bowl and stir in the sugar. Pour the melted butter over the crumbs and mix thoroughly. Press the mixture evenly into a 9-inch pie plate.
Bake the empty crust for 8 to 10 minutes, until a dark golden brown. Cool the crust on a wire rack for at least 30 minutes before filling. You can also make it a day ahead, and store it in the refrigerator.
Next, make the filling:
Lower the oven temperature to 325 degrees.
Whisk the egg yolk and lime zest together in a bowl for about 2 minutes, until a light greenish yellow color. Whisk in the milk, then the lime juice, and set aside at room temperature for about 5 minutes, until the filling thickens, and the whisk leaves tracks in it. Spread the filling evenly in the crust.
Bake for about 15 minutes, until almost completely set. The filling should wobble a bit when the pan is jiggled. Cool to room temperature on a wire rack, then chill in the refrigerator for at least 3 hours before slicing.