four 5-inch tart pans with removeable bottoms; kitchen torch
Preheat the oven to 375 degrees F.
For the crust: Pulse the flour, almonds, sugar and salt in a food processor until the nuts are finely ground. Add the butter and pulse until the mixture looks like coarse meal. Add the ice water and pulse until the dough starts coming together.
Turn the dough out onto a piece of plastic wrap, pat into a disk and wrap in the plastic. Refrigerate until cold but still malleable, about 15 minutes.
In the meantime, make your curd filling: Combine the sugar, cornstarch and salt in a saucepan and whisk to combine. Stir in the peach nectar, egg yolks and lemon juice. Bring to a simmer over medium heat. Cook, whisking constantly, until the filling thickens and coats the back of a spoon; this will take 5 to 7 minutes after it comes to a simmer.
Remove from the heat and stir in the butter, a tablespoon at a time. Strain the filling into a 9-by-13-inch glass baking dish. Cover with a sheet of plastic wrap to prevent a skin from forming and chill completely, about 1 hour.
While your filling is chilling, lightly spray four 5-inch tart pans with removable bottoms with nonstick cooking spray. Divide your chilled tart dough into 4 pieces, then press into the bottom and up the sides of each prepared pan. Freeze until firm, about 10 minutes. Use a paring knife to trim any excess dough.
Place the tart shells on a baking sheet, line each shell with parchment and fill with pie weights or dried beans. Bake until golden around the edges, about 20 minutes. Remove the parchment and weights and continue baking until the crusts are golden brown all over, 5 to 10 more minutes. Let cool completely.
Divide the chilled curd/custard among the tart shells. Put back into the refrigerator while you make the meringue.
In the meantime, make your meringue: Add the sugar and water to a saucepan over high heat. Bring to a boil, then once at a boil, cook for 4 minutes.
While your sugar is cooking, put your egg whites, cream of tartar and salt into the bowl of a stand mixer fitted with a whisk attachment and beat on low speed. When the sugar mixture on the stovetop comes to a boil, turn the mixer to high speed.
When the sugar syrup is ready, turn the mixer to medium-low speed. Pour the syrup in a steady stream in between the side of the bowl and the whisk attachment while the mixer is running. Turn the mixer to high and beat for 2 full minutes. Transfer the meringue to a pastry bag fitted with desired tip.
Pipe decorative designs with the meringue on the tarts. Use a pastry torch to brown. Garnish with basil leaves and serve.
Propane gas torches are highly flammable and should be kept away from heat, open flame and prolonged exposure to sunlight. They should be used only in well-ventilated areas. Follow torch manufacturer's instructions for use.