This classic French dessert — essentially a doubled version of an Alice Medrich recipe, although David Lebovitz uses the same proportions — is nothing more than a sweet tart crust filled with lemon curd. Buy organic or unsprayed lemons if you can, and Meyer lemons if they’re available. Or use limes (try Key limes) for a zingier version.

Steps

1. Make the crust: Place a rack in the lower third of the oven. Preheat the oven to 350 degrees.
2. In a medium bowl, combine the melted butter with the sugar, vanilla, and salt. Add the flour and mix just until blended. Set aside for a few minutes to firm up.
3. Press the dough evenly over the bottom and up the sides of a 10- or 11-inch fluted tart pan with a removable bottom. (You can also use two 9-inch pie plates, or 4 to 6 smaller tart pans.)
4. Bake until the crust is a deep golden brown, about 20 to 25 minutes.
5. Make the filling: While the crust is baking, whisk together the eggs and yolks in a small bowl.
6. In a small saucepan, combine the lemon zest, juice, sugar, and butter, and bring to a simmer over medium heat.
7. Gradually pour the hot liquid over the eggs, whisking constantly. Scrape the mixture back into the saucepan and whisk over medium heat until thickened and just beginning to simmer around the edges.
8. Scrape the mixture into a medium-mesh strainer set over a clean bowl. Tap the strainer against the side of the bowl so that the mixture sieves through, leaving behind the zest and bits of cooked egg white. Scrape any strained filling clinging to the underside of the strainer into the bowl as well.
9. Assemble the tart: When the crust is golden brown, remove it from the oven. Pour the filling onto the hot crust and spread it evenly over the crust. Arrange the lemon slices atop the tart, if you wish.
10. Return the tart to the oven for five minutes, to set the filling a bit more, or simply cool the tart as is, on a rack.
11. Serve at room temperature or chilled. (If you want a more firmly set filling, chill the tart first.) Store in the refrigerator if you aren’t serving it within a few hours.