Mini Key Lime Meringue Tartlets

Directions

To make the crust:

Add the butter in a medium bowl, beat with an electric mixer on medium-high until smooth.

Beat in the sugar and salt until well blended.

Scrape down the sides of the bowl if needed, then beat in the egg yolk.

Beat in half of the flour until just crumbly.

Scrape down the bowl, beat in remaining flour and then the yogurt or sour cream, beating until the dough is just incorporated.

Transfer the dough onto a lightly floured working surface or a cutting board and knead lightly to bring it together.

Roll the dough between 2 generously floured sheets of waxed paper into a circle about ¼ inch thick with a rolling pin.

Refrigerate for 1 hour.

Cut out 6 (4½-inch) rounds using an inverted bowl or round cookie cutter.

Arrange rounds in the muffin tins and, using a small shot glass or your fingers, press into the corners and about halfway up the sides for a snug fit.

Freeze dough in the muffin tin for half an hour.

Put a rack in the lower third of the oven and preheat to 325℉ (160℃).

Coat the outside of 6 standard muffin liners with cooking spray and transfer in the crusts.

Fill with dried beans or pie weights.

Bake until start to brown around the edges, about 25 to 30 minutes.

Remove from the oven and cool for about 2 minutes, then carefully remove the muffin liners and baking beans or pie weight.

Bring the pan back to the oven and keep baking until crusts are cooked through and evenly browned, about 18 to 22 minutes more. Cool for a few minutes in the muffin tins on a wire rack.

Carefully remove crusts from the muffin tin and let cool completely on a rack.

To make the Lemon Filling:

Add the sugar, cornstarch, and yolks in a saucepan over medium-low heat.

Whisk frequently until the mixture is smooth and sugar dissolves, 1 to 2 minutes.

Stir in the key lime juice and keep cooking, whisking frequently, until the mixture is as thick as sour cream and is just about to simmer, about 4 minutes. (Make sure to stir into the sides of the pot so that all curd thickens evenly.)

Strain through a fine mesh strainer into a bowl.

Whisk in the butter a little at a time, until smooth.

Stir often until cool to room temperature. (Setting the bowl in a larger bowl of ice will speed the process up.).

Fill each mini tart with about 4½ tablespoons of the cool lime filling.

To make the Meringue:

Bring a few inches of water to a boil in a saucepan that can hold a standing mixer's bowl above the water.

Use your hand to whisk together the egg whites, sugar, cream of tartar and salt in the bowl.

Place the bowl above the boiling water and keep whisking until the mixture is hot to the touch (135 degrees F) and the sugar dissolves, about 2 minutes.

Transfer the bowl to the mixer fitted with the whisk attachment and beat the whites at medium-high speed until they hold soft peaks.

Increase speed to high and go on beating to make a soft and glossy meringue, about 2 minutes.

Dollop or pipe on top of the filling.

Just before serving, preheat the broiler to high.

Set the tartlets on a baking sheet, and place under the broiler until the meringue is evenly baked, about 2 minutes. (Alternatively, brown meringue with a blowtorch.)

Serve right away or keep refrigerate until ready to serve.

Notes:

They can be stored in the refrigerator for up to 2 days.

Or they can be frozen very well.

They can be prepared, assembled and frozen up to 1 week in advance.

Defrost for 20 minutes before broiling the tops and serving.

The crusts can be made, baked and frozen up to 2 weeks.

The curd can be made up to 3 days ahead and keep refrigerate.

The meringue can be made up to 1 day ahead and keep refrigerate.