Prepare

First make the crust: Very briefly pulse the flour, butter, sugar, and salt in a food processor. Add enough cold water for the dough to start coming together. Swiftly shape into a ball, wrap in plastic wrap, and let the dough rest in the fridge for 1 hour.

Preheat the oven to 350°F (180°C). Grease the baking pan or a 12-cup muffin tin with butter.

Roll out the dough to less than ⅛ inch (3 mm) thick on a floured countertop and then use it to line your baking pan(s). Neatly trim the edges. Line each crust with a sheet of parchment paper and fill with pie weights or dried beans. Blind bake a large crust for 20 to 25 minutes, until cooked through and dry; bake small crusts for about 15 minutes. Remove the weights and parchment and return the crusts to the oven for another 8 to 10 minutes, until the crust is golden brown but the edges haven’t browned too much. Let the crust(s) cool on a rack.

Make the blood orange curd: Combine the blood orange juice, lemon juice, egg yolks, cornstarch, and sugar in a saucepan. While stirring, bring to a gentle boil and continue stirring until all of the sugar has dissolved and the mixture has thickened.

Remove from the heat and stir in the butter, one piece at a time, until it is all incorporated. Pour the filling into the cooled crust(s). Set aside in a cool place. Allow the curd to solidify.

Make

Make the meringue: In the bowl of a stand mixer fitted with the whisk attachment, whip the egg whites together with the 2 tablespoons sugar and the salt until firm peaks form.

Meanwhile, in a saucepan, melt the remaining 1 cup (200 g) sugar with 3 tablespoons water to make a syrup; heat until the syrup reaches 250°F (121°C) on a candy thermometer, about 10 minutes.

Pour the hot syrup into the egg white mixture while whisking and continue whisking until the meringue is thick and glossy and feels just warm to the touch. Scoop or pipe the foam onto the cooled tart(s).

Quickly brown the top with a crème brulée (kitchen) torch or place the tart(s) under a preheated broiler for a few minutes, turning them to evenly brown the tops. Keep a good eye on the meringue, as it may burn before you know it. Serve.