Preheat oven to 375ºF. Spray a 24-cavity mini muffin tin with baking spray.

Cut out 24 circles with a 2.25" or 2.5" round cookie cutter from pie crusts. Place them over the top of each muffin cavity. Then using a shot glass, press down over the center of each pie crust circle and press down to create the mini pie shells. Prick the bottom of each pie shell 1-2 times with a fork.

Place mini muffin liners or small squares of aluminum foil over the top of each pie crust and fill with pie weights (dry beans work well too). Bake for 10-12 minutes. Remove from the oven and let cool completely. Baked pie shells can be kept in an airtight container at room temperature for 2-3 days.

In a medium-sized saucepan, mix together the egg yolks, granulated sugar, cornstarch, lemon zest, lemon juice, and unsalted butter, whisking continually over low-medium heat until the lemon curd has thickened (about 5-6 minutes).

Remove the lemon curd from heat and, using a spatula, press the lemon curd through a fine-mesh sieve into a mixing bowl. Add a layer of plastic wrap directly over top of the lemon curd (to avoid getting a film over the top) and chill in the refrigerator for a minimum of 1 hour, or overnight. Kept in a tightly sealed container, lemon curd will last up to a week in the refrigerator.

Using your hand mixer and a medium-size mixing bowl or your stand mixer and the whisk attachment, beat the egg whites and cream of tartar on medium-high speed until soft peaks form.

Add in the granulated sugar, then mix for another 8-10 min until stiff peaks form.

Using a small or medium-size piping bag or spoon, fill each baked mini pie shell with the lemon curd filling. I recommend filling them only half full.

Fill a medium-size piping bag with the meringue and pipe the tops of each mini lemon pie. Lightly brown the tops of each meringue with a kitchen blow torch.