Key lime pie’s more elegant cousin — Key lime tart — is ready to claim its rightful place in the dessert world. This tart fulfills everything we all love about Key lime pie and it's dressed to impress, with its delicate fluted edges and a whipped cream garnish.
To make the crust: Stir together all the crust ingredients, mixing until thoroughly combined.
Press the crumbs into the bottom and up the sides of a 9” round tart pan or 10 1/2" x 6 1/2" rectangular tart pan. Freeze the crust for 15 to 20 minutes while you preheat the oven to 325°F.
Place the crust on a baking sheet (to catch any melting butter) and bake it for 10 to 12 minutes, until lightly browned. Remove the crust from the oven and place it on a rack to cool slightly, while you make the filling.
To make the filling: Whisk the lime zest and egg yolks at high speed of an electric mixer for about 4 minutes. The mixture will lighten in color and thicken somewhat, appearing similar to Hollandaise sauce.
Stir in the sweetened condensed milk, mixing until smooth. Beat at high speed for 3 minutes; the filling will become slightly thicker and gain a bit of volume.
Add the lime juice, stirring just to combine. The mixture will thicken again. Add lime oil to taste.
Pour the filling into the crust and return the tart (on the baking sheet) to the oven. Bake the tart for 18 to 22 minutes, until it appears set around the edges though still a bit wobbly in the center. The center should read about 145°F on a digital thermometer.
Remove the tart from the oven and cool to room temperature. Refrigerate for several hours before serving.
To make the topping: Combine the cream and confectioners’ sugar in a mixing bowl, and whip until medium peaks form. Pipe or spread the cream onto the tart and serve.
Store any leftover tart in the refrigerator for up to three days.
