Step 1Stir together the flour and salt. Cut the butter into the flour mixture with a pastry blender or by hand until the ingredients are combined and the mixture resembles coarse meal.
Step 2Sprinkle in the ice water. Quickly stir the water into the flour mixture with a fork just until the dough holds together.
Step 3Shape the dough into a ball, then flatten it into a 1-inch-thick circle. Cover in plastic wrap and refrigerate 30 minutes.
Step 4Roll the dough into a 15-inch circle on a lightly floured board. Lift the pastry onto a 9-inch pie plate and gently fit it into the bottom and up the sides of the pie plate. Trim the edges, leaving a 2-inch overhang. Flute and crimp. Chill the shell 30 minutes.
Step 5Heat the oven to 475 degrees. Line the pie shell with a piece of parchment and fill with pie weights. Bake 15 minutes. Remove the parchment and pie weights and continue to bake until the crust is golden brown, about 3 to 5 minutes. Cool to room temperature.
Step 1Combine the cornstarch, sugar and salt in a saucepan. Gradually add the boiling water and stir until blended.
Step 2Heat the mixture over medium heat, stirring, until it boils and the mixture is clear and has thickened,
Step 34 to 5 minutes. Pour the filling into the top of a double boiler or into a metal bowl set over a pan of simmering water and cook 10 minutes, stirring occasionally.
Step 4Add a small amount of the hot mixture to the beaten egg yolks and return all to the pan, stirring until blended. Cook 2 minutes.
Step 5Remove from the heat. Stir in the lemon juice, butter and lemon zest. Place plastic wrap on top of the filling and cool to room temperature.
Step 6Pour the filling into the baked pie shell, spreading it evenly.
Step 1Beat the egg whites and cream of tartar until frothy. Continue beating until soft peaks form.
Step 2Slowly add the sugar, beating until the mixture is stiff but not dry.
Step 3Spoon the meringue onto the pie filling. Spread and swirl the meringue over the filling, sealing to the edges of the pie.
Step 4Bake at 400 degrees until the meringue peaks are golden brown, about 8 to 10 minutes. Cool to room temperature.