I thought about calling these Lime Curd Tarts because, essentially, that is what they are: a layer of the chartreuse-colored confection in a graham cracker crust, topped with a towering pouf of white chocolate mousse. But “curd” is one of those words that belong in the annals of unfortunate culinary terms—alongside treacle, clotted cream, black pudding and spotted dick—names that hide the delicious reality behind a veneer of implied grossness.
The ratio of lime curd to mousse in this recipe is about 1:2; the curd is intensely lime-y, and I feel that a little goes a long way. However, if you love lime-y, feel free to double the lime curd recipe and fill your tart shells to the brim!
But no matter how you stack your tart, you will have extra mousse. And that’s a good thing.
Makes 4 (4-inch) tarts
For the crust:
1 cup fine graham cracker crumbs
½ teaspoon sea salt
4 tablespoons melted butter
For the curd:
3 egg yolks
⅓ cup freshly squeezed lime juice
½ cup granulated sugar
Pinch sea salt
4 tablespoons butter
Grated zest of ½ lime
For the mousse:
7 ounces white chocolate
4 ounces whole milk
12 ounces heavy cream
⅛–¼ teaspoon grated lime zest
Slice of lime, for garnish
Fresh mint leaves, for garnish
Preheat oven to 350°F. Have ready four 3- or 4-inch tart pans with removable bottoms.
In a small bowl, mix the graham cracker crumbs with ½ teaspoon sea salt, and then stir in the 4 tablespoons of melted butter. The mixture should resemble coarse sand.
Place about 3 tablespoons of the graham cracker mixture into each tart pan and with your fingers press the mixture all along the bottom and up the sides, creating a crust with even thickness.
Place the crusts in a 9 x 9-inch baking dish and bake for 10 minutes, or until the edges of the crusts are just beginning to brown. Remove them from the oven and allow them to cool.
Bring a couple of inches of water to a simmer in a medium saucepan. In a medium-sized bowl, whisk together the yolks, lime juice, granulated sugar and pinch of salt. Place the bowl over the simmering water and add the butter in teaspoon-sized bits.
Cook the mixture, stirring often, over (but not touching) the simmering water until it is thickened and holds a very soft shape when dropped onto itself with a spoon. Remove the curd from the heat and push through a strainer into a clean bowl. Stir in the lime zest, then divide the curd evenly between the tart shells. Refrigerate the tarts until the curd is firm, about an hour or more.
Meanwhile, place the chopped white chocolate into a heatproof bowl. Bring the milk to a full boil in a small saucepan over medium heat. Pour the milk all at once over the white chocolate and let it sit for 1 full minute. Gently whisk the chocolate and milk together until all the chocolate has melted and the mixture is completely emulsified. Stir in the grated lime zest.
Place the heavy cream into a large bowl and beat enthusiastically with a whisk (or with a handheld electric mixer with whisk attachment) until the cream forms soft, pillowy peaks.
Add the whipped cream in 2 additions to the chocolate ganache, folding very gently with a large rubber spatula until the mousse is completely homogenous with a satiny texture. Try not to over mix the mousse, as doing so will create a slightly grainy texture.
Remove the cooled tarts from the refrigerator and carefully remove the outer rings (I do this by heating the sides of the tart rings over a burner flame, or with a hairdryer). Gently release the bottom of the tart pan from the crust, and slide the tart onto a serving plate.
Spoon a generous amount of mousse onto the curd, so that it billows over the rim of the crust. Garnish as desired, and serve immediately, or refrigerate until ready to serve.