Step 2

Make the Lemon Pie: Roll out the pie crust to ¼ inch thick. Roll the dough onto the rolling pin, then gently transfer it to the pie plate. Chill for 10 minutes.

Step 3

Fold the excess pie dough under itself all around the edge of the pie plate, then crimp as desired. Prick the base all over with a fork and then refrigerate the dough for 20 minutes. Preheat the oven to 425°F.

Step 4

Cut a piece of parchment paper into a round slightly larger than the base of the pie plate. Place it in the chilled pie crust and fill with dried beans or pie weights. Bake until the crust is beginning to brown lightly at the edges, 15 to 17 minutes. Remove the pie weights and continue to bake for about 5 more minutes. Remove the crust from the oven and cool completely. Lower the oven temperature to 375°F.

Step 5

Whisk the egg yolks together in a medium bowl. Whisk in ½ cup of the sugar.

Step 6

In a medium saucepan, whisk together the cornstarch, salt and remaining sugar. Add 1½ cups water and begin to heat the mixture over medium heat, whisking constantly. Bring the mixture to a boil; boil for 1 minute.

Step 7

Gradually pour about a third of the cornstarch mixture into the egg yolks, whisking constantly to combine. Add the yolk mixture to the pot, pouring in a slow, steady stream and whisking constantly.

Step 8

Heat the mixture over medium heat, stirring constantly, until it begins to bubble. Once large bubbles appear on the surface, continue to cook for 30 seconds, stirring constantly.

Step 9

Stir in the lemon juice and butter, mixing well to combine. Strain the mixture through a fine-mesh sieve into the cooled pie crust (this will ensure a lump-free filling) and smooth into an even layer. Bake until the filling is just barely set (it will still look a bit jiggly), 15 to 17 minutes. Cool to room temperature, then chill until firm, at least 1 hour.

Step 10

Make the Blueberry Meringue: In a blender or food processor, pulse the blueberries until they form a fine powder (you should end up with about 2 tablespoons blueberry "powder"). Transfer to a medium saucepan and whisk in the sugar. Add ? cup water to the saucepan and heat over medium heat.

Step 11

Stir the mixture until it comes to a boil; once it boils, stop stirring. If any sugar crystals have washed up on the side of the saucepan, brush them away using a pastry brush dipped in cool water. Boil the sugar syrup until it reads 230°F on a candy thermometer.

Step 12

Meanwhile, place the egg whites and cream of tartar in the bowl of an electric mixer fitted with the whisk attachment. When the syrup reaches 230°F, begin whipping the egg whites on medium-high speed. The goal is to have the egg whites at soft peaks when the sugar reaches 240°F.

Step 13

Slowly pour the sugar syrup into the egg whites, then continue to whip until it reaches medium peaks, 4 to 6 more minutes. Spoon the meringue on top of the cooled pie and swoosh with the back of a spoon into an even, centered mound. If desired, you can toast the meringue with a kitchen torch or under the broiler, but it will be a prettier color if it's left untoasted, and it's safe to eat because the hot sugar syrup cooks the eggs.