I was a fan of key lime pie way before I actually made it to Key West, but it was a joy to try the real deal. Here's my version that I've served a several dinner parties and always is a hit. I love how easy it is to put together. The most time consuming part of this recipe is juicing the limes. I've posted this recipe before, but here's a refresher! 
Lime Tart with Gingersnap Crust (recipe adapted from Cook's Illustrated, The Best Recipe)
1 1/2 cups gingersnap crumbs, ground in a food processor from gingersnap cookies
2 Tbsp sugar
4 Tbsp butter, melted
dash of cinnamon
Pulse the gingersnaps in a food processor until uniformly ground. Add the sugar and cinnamon. Pulse a few more times to incorporate. Remove the gingersnap crumbs to a mixing bowl. Stir in the melted butter until well combined. Press the crumbs evenly over the bottom and up the sides of a buttered tart pan. Using plastic wrap helps prevents the crumbs sticking to your fingers.
Bake the crust at 325 degrees F for 15 minutes. Remove from the oven and let cool for 15-20 minutes. You don't want to pour the filling into a piping hot crust.
1 (14 oz) can sweetened condensed milk
1/2 cup fresh lime juice, strained
4 egg yolks
2 Tbsp grated lime zest
Whisk together the egg yolks and lime zest in a medium bowl for several minutes. (Cook's Illustrated says this turns the yolks a pale green, but I didn't find this to be true.) Whisk in the condensed milk and then the lime juice. Let this mixture rest just a few minutes to thicken.
Once the crust has mostly cooled, pour the filling into the crust. Bake at 325 degrees F for 15-17 minutes or until the filling is almost set, but still wobbly in the center. Cool again until the tart is at room temperature, then refrigerate for about 3 hours until well chilled.
Whipped Cream:
1 cup heavy whipping cream
3 Tbsp confectioner's sugar
Beat the heavy cream on medium speed with an electric mixer until soft peaks form. Gradually beat in the sugar until smooth and stiffer peaks form. Using a pastry bag with a small star tip, pipe the whipped cream over the tart in whatever way your technique allows! OR when I don't have much time to put it together, I skip the pastry bag and decorate the top with fruit.
