Lemon Tart (Tarte au Citron)

Preheat the oven to 350° F. Generously butter and flour a 9” fluted tart pan with a removable bottom and refrigerate it while the oven preheats.

Remove the tart pan from the refrigerator. Use your fingertips to press the chilled dough evenly over the bottom and up the sides of the pan. Trim off any excess dough. Bake the crust for 10 to 15 minutes, then rotate it and bake for another 10 to 15 minutes, or until it is golden brown. Remove the crust from the oven and let it cool while you make the filling.

In a double boiler bowl, whisk the eggs, yolks, and sugar for about 1 minute, or until the mixture is smooth. Set the bowl over the pot and whisk. After 2 minutes, when the eggs are foamy and have thickened, add ⅓ of the lemon juice. Continue to whisk vigorously and, when the mixture thickens again, add another ⅓ of the lemon juice. Whisk until the mixture thickens again, then add the remaining lemon juice. Continue whisking vigorously, turning the bowl, until the mixture is thickened and light in color and the whisk leaves a trail in the bottom of the bowl. The total cooking time should be 8 to 10 minutes.

Turn off the heat and leave the bowl over the water. Whisk in the butter a piece at a time. The filling may loosen slightly, but it will thicken and set as it cools. Pour the warm filling into the tart crust and place the pan on a baking sheet.

Preheat the broiler. While the filling is still warm, place the tart under the broiler. Leaving the oven door open, brown the top of the filling, rotating the tart if necessary for even color; this will take only a few seconds, so do not leave the oven. Remove the tart from the broiler and let it set for at least 1 hour before serving. Serve at room temperature or cold.