For the crust:
1/2 pound unsalted butter, at room temperature
1/2 cup granulated sugar
2 cups flour
1/8 teaspoon salt
For the filling:
7 large or 6 extra-large eggs at room temperature
3 cups granulated sugar
2 tablespoons grated lemon zest (4 to 6 lemons)
1 cup freshly squeezed lemon juice (2-4 lemons) Don't bother with purchased lemon juice. Its just not the same.
1 cup flour
Confectioners' sugar, for dusting
Preheat the oven to 350 degrees F.
For the crust, cream the butter and sugar until light in the bowl of an electric mixer fitted with the paddle attachment. Combine the flour and salt and, with the mixer on low, add to the butter until just mixed. Dup the dough into a 9 by 13 by 2-inch baking sheet. Flatten the dough with floured hands and press firmly building up a 1/2-inch edge on all sides.
Bake the crust for 15 to 20 minutes, until very lightly browned. Let cool completely on a wire rack.
Leave the oven on.