10 full graham cracker sheets
2 tbsp granulated sugar
6 tbsp melted butter
1 tbsp key lime zest, divided
4 large eggs, divided
1/2 cup key lime juice
1 1/4 cups Homemade Sweetened Condensed Milk (recipe below, and see note above) or 1 14 oz can sweetened condensed milk
Preheat oven to 350˚F. Crush the graham crackers into crumbs by pulsing in a food processor, or adding to a plastic baggie and crushing with a rolling pin. Add to a bowl and stir in the butter, sugar and half the lime zest. Press crust into a 9 inch pie plate and bake for 5-7 minutes, or until golden brown. Set aside to cool.
Meanwhile, whisk together the remaining zest, egg yolks (reserve the whites for the meringue topping), lime juice and sweetened condensed milk. Pour into the cooled pie crust and bake for about 20 minutes, or until set. Let cool, then chill in the fridge for at least 4 hours, preferably overnight. Serve as is, or add meringue topping (recipe below).
4 large egg whites
3/4 cup granulated sugar
1/2 teaspoon pure vanilla extract
1/4 teaspoon cream of tartar
To Make the Meringue Topping:
Set up a clean double boiler. When the water is simmering, add egg whites and sugar and whisk until the sugar has dissolved, about 3 minutes. Transfer the egg whites to the bowl of the mixer and add the vanilla extract and cream of tartar. Whip (with the whisk attachment) on high for about 5-7 minutes, or until the mix starts to become stiff and glossy. You’ll know the mixture is ready when it will hold a stiff peak without deflating. Add topping to prepared pie and smooth with the back of a wooden spoon, creating some peaks for decoration.
To Brown Meringue:
If using a broiler, set oven rack about 8 inches below the flame and preheat for about 5 minutes. Add brownies and keep a close eye on them, adjusting the pan as needed so that they brown evenly.
Or, if you are using a kitchen torch, torch topping by moving the flame in circular motions so not to stay in one spot for too long (it will burn) over the meringue until the surface is evenly browned.
Homemade Sweetened Condensed Milk
2 cups whole milk
2/3 cup sugar
2 tbsp butter
1 tsp vanilla extract (optional)
Add milk and sugar to a small saucepan and bring to a simmer over medium heat. Reduce heat to low and cook for about 3 hours, stirring often, or until thickened and reduce by half. Remove from heat and stir in the butter and vanilla extract (if using). Let cool and store in an airtight jar in the fridge for up to one week.