Key Lime Pie

1. Preheat oven to 325 degrees.

To make the filling:

1. In a medium bowl, whisk together egg yolks and lime zest until lightly green, about 2 minutes. 
2. Whisk in condensed milk until smooth, then whisk in lime juice. Cover and let sit at room temperature until thickened, about 30 minutes.

To make the crust:

1. In a food processor, or in a plastic bag with a rolling pin, finely crush graham crackers.
2. In a medium bowl, combine graham cracker crumbs, butter, and sugar. Pour into a 9-inch pie plate, using the bottom of a measuring cup to press the crust evenly and firmly into the bottom and up the sides of the pie plate.
3. Bake until golden brown and fragrant, 15 to 20 minutes. Remove from oven and transfer to wire rack (do not turn off oven). 

To assemble the pie:

1. Pour thickened filling into warm pie crust. Bake until center is firm but still jiggly when shaken, 15 to 20 minutes. Transfer to wire rack and cool 1 hour.
2. Cover pie loosely with plastic wrap and refrigerate until filling is chilled, at least 3 hours or up to 24 hours.

To make the topping:

1. In a stand mixer fit with the whisk attachment, or with an electric mixer, whip cream and sugar on medium-low speed until foamy, about 1 minute. 
2. Increase speed to high until soft peaks form, about 1 to 3 minutes. Spread whipped cream over the top of pie or pipe a design around the edge. Garnish with lime zest.