1 1/2 cups graham cracker crumbs, (about 15 crackers)
6 tablespoons unsalted butter, melted and cooled
6 large egg yolks
1 cup freshly squeezed key lime juice
2 cans (14 ounces) sweetened condensed milk
1 tablespoon finely grated Key lime zest
Preheat oven to 375 degrees.
Combine the cracker crumbs and butter in a medium bowl, and mix until moist. Evenly press mixture into a 9-inch pie plate, and bake until lightly browned, about 12 minutes. Remove from oven, and transfer to a wire rack until completely cooled.
In a medium heatproof bowl, whisk the yolks and lime juice together until combined. Set bowl over a saucepan of simmering water, and cook, whisking constantly, until mixture is foamy and registers 160 degrees.on an instant-read thermometer, about 6 minutes. Remove bowl from heat, and whisk in condensed milk and zest until well combined. Pour into cooled pie shell and smooth top with a rubber spatula. Freeze until firm, 3 hours.
Remove pie from freezer 5 minutes before serving. Serve immediately.
