Graham Cracker Crust
1 paper-wrapped package graham crackers
5 tablespoons melted unsalted butter
1/3 cup sugar

Filling
3 egg yolks
1 1/2 teaspoons lime zest (about 2 limes)
1 (14-ounce) can sweetened condensed milk
2/3 cup freshly squeezed key lime juice

Topping
1 cup whipping cream, chilled
3 tablespoons of confectioners' sugar

Instructions
Preheat the oven to 350 degrees F. Butter a 9-inch pie pan. Break up the graham crackers: place in a food processor and process to crumbs. Add the melted butter and sugar and pulse or stir until combined. Press the mixture into the bottom and sides of the pan. Bake the crust until set and golden, 8 minutes. Set aside on a wire rack.

Beat the egg yolks and lime zest at a high speed until very fluffy, abut 5 minutes. Gradually add the condensed milk and continue to beat until thick, 3 or 4 minutes longer. Lower the mixer speed and slowly add the lime juice, mixing just until combined. Pour mixture into the pie crust. Bake for 10 minutes, or until the filling has set. Cool on a wire rack, then refrigerate. Freeze for 15 to 20 minutes before serving.

Whip the cream and the confectioners' sugar until nearly stiff. Cut the pie in wedges and serve very cold, topping each wedge with a large dollop of whipped cream.