Key Lime Pie

Ingredients

• 10 whole graham crackers
• 1/2 teaspoon kosher salt
• 3 tablespoons granulated sugar
• 2.5 ounces melted butter, cooled
• 14 ounces sweetened condensed milk
• 4 egg yolks
• 4 ounces freshly squeezed key lime juice
• 1 tablespoon key lime zest, plus more for decoration
• 6 ounces heavy cream
• 2 tablespoons confectioner's sugar
• 1/4 cup mascarpone cheese, optional

Directions

1. Heat the oven to 375 degrees F. Put the graham crackers, salt, and sugar in the bowl of a food processor, and blitz for approximately 30 seconds, until the crackers are evenly crushed into fine crumbs. Pour in the melted butter and pulse until the crumbs are moistened. Press the mixture across the bottom and up the sides of the springform pan, keeping the crust on the sides to about 1 1/2 inches. Set the crust in the fridge for 15 minutes, then bake it for 10 minutes. Let the crust cool all the way, and turn the oven down to 325 degrees F.
2. In the bowl of the food processor, add the sweetened condensed milk, egg yolks, key lime juice, and zest. Blend for 10 seconds, pause to scrape the sides, then blend again for another 10 seconds. Spoon the filling into the cooled crust. Bake at 325 degrees F for 14 to 17 minutes, until the filling is set but the middle still has a little wobble. Keep an eye on it, because this pie firms up fast. Let it come to room temperature, then move the pie to the fridge to chill completely, for at least 4 hours.
3. Just before serving, unclasp the springform pan and lift off the sides. Put the heavy cream and confectioner's sugar in a bowl and whisk by hand, or use a stand mixer fitted with the whisk attachment, until medium peaks form. If you are using the mascarpone, whisk it in until smooth and thick. Pipe or spread the cream mixture over the pie, then sprinkle the top with key lime zest. Serve immediately.