It helps to know: This recipe requires uncooked rice or dried beans for weighting the crust.

• First make the crust.
• (This is easily done by pulsing in a food processor, but since I already made you buy a scale, I’ll explain it the low-tech way.
• ) In a large bowl, cream together the butter and confectioners’ sugar using a wooden spoon until well combined (it will look fluffy and lighter in color).
• Beat in one egg until fully incorporated.
• Repeat with the second egg.
• Sift in the flour, cornstarch, and salt and continue to beat until a dough has formed.
• Shape the dough into a ball and flatten it with the palm of your hand.
• Wrap in plastic and place in your refrigerator to chill for 1 hour.
• Preheat your oven to 375°F.
• Grease a 9- to 11-inch tart mold with 2 teaspoons butter.
• Remove the dough from your refrigerator and place it between a folded piece of parchment paper to prevent sticking.
• Roll the dough into a circle about ¼ inch thick and a bit larger than your tart mold.
• Carefully transfer the rolled-out dough to your buttered tart mold.
• Use your fingers to gently press the dough into the sides of the tart mold, then cut off any excess dough draping over the top—you want the crust to just come to the top of your mold.
• Use a fork to poke holes across the bottom of the tart shell to prevent it from puffing up as it bakes.
• Line the shell with cheesecloth, draping it over the side of the mold to prevent the edges from burning.
• Fill the cheesecloth with a ½-inch layer of uncooked rice or dried beans to make a weight that prevents the dough from puffing.
• Return the dough to your refrigerator to chill until firm, about 5 minutes.
• Bake until the shell is nicely browned around the edges, about 25 minutes.
• Remove and discard the weights and cheesecloth and continue to bake until the middle is browned, about 5 minutes more.
• Remove the crust from your oven and set aside to cool.
• To make the filling, grate the zest from the lemons into a large bowl.
• Juice the lemons into a separate bowl, then strain the juice into the bowl with the zest.
• Whisk in the eggs and granulated sugar.
• Pour the mixture into a saucepan on medium-low heat.
• Using a wooden spoon, stir constantly until the mixture begins to thicken.
• Never allow the mixture to boil or it will curdle.
• (If it does curdle, don’t panic!
• Keep reducing it, add the butter, and then transfer it to a blender and blend until smooth.
• ) Once the mixture has thickened considerably, 10 to 15 minutes, pour it into a large bowl.
• Stir in the butter, 1 tablespoon at a time, until all of the butter has been incorporated.
• Pour the filling into your tart shell and let cool to room temperature to set the filling.
• Cover the tart with plastic wrap and chill in your refrigerator for at least 1 hour, or ideally overnight.
• Remove 10 minutes before serving.
• Leftovers can be stored, covered, in your refrigerator for up to 5 days.