After pre-baking the crust, look for any cracks that the filling could seep through. Make a paste of about 1 teaspoon of flour and 1/2 teaspoon of water, and smear it over the cracks with your fingers to seal them.
Serves 10
1/2 cup (1 stick) unsalted butter
2 Tbsp finely grated lemon zest
1 3/4 cups all-purpose flour
1 1/4 cups granulated sugar
2 pinches of salt
6 large eggs
1 cup fresh-squeezed lemon juice
1/2 cup heavy cream
Confectioner's sugar for dusting
Position a rack in the middle of the oven and preheat the oven to 350° F. Have ready an 11-inch tart pan with a removable bottom.
Melt the butter in a small saucepan over medium heat, add 1 Tbsp of the zest, and let stand for 5 minutes. Whisk together the flour, 1/4 cup of the granulated sugar, and a pinch of salt in a medium bowl. Pour in the butter mixture in a fine stream, stirring with a fork, and continue stirring until the dough begins to come together when a small bit is pressed between your fingers. Transfer the mixture to the tart pan and press it with your fingertips evenly up the side and into the bottom. Bake for 20 minutes, or until the crust is light golden brown. Let cool on a wire rack while making the filling.
Process the remaining 1 cup of granulated sugar and the remaining 1 Tbsp of zest in a food processor until the zest is finely ground.
Whisk together the eggs, the sugar and zest mixture, the lemon juice, and another pinch of salt in a medium bowl until smooth.
Beat the cream with an electric mixer on medium-high speed in a medium bowl just until it forms soft peaks. Whisk the cream into the egg mixture just until blended.
Place a baking sheet in the oven, place the crust on the baking sheet, and pour the filling into the still warm crust. Bake for 25 to 30 minutes, or until the filling is just set in the center. Let the pie cool on a wire rack.
Just before serving, generously sift confectioners' sugar over the tart. Cut into wedges and serve.