STEP - 1
Bake crust: Preheat oven to 375°. On a lightly floured surface, roll out dough into a 12” circle. Drape over 9” pie dish and gently press to fit (don’t stretch). Prick bottom with a fork, trim edge to 1”, and tuck overhang under itself, and crimp. Refrigerate 30 minutes or freeze 10 minutes. STEP - 2
Line crust with parchment and fill with dried beans or pie weights. Bake 30 minutes, then remove parchment and weights. Return to oven and bake until crust is golden and completely baked through, 20 to 25 minutes more. Set on rack to let cool completely.
STEP - 3
Meanwhile, make filling: In a saucepan over medium heat, combine 1 1/4 cups sugar, cornstarch, flour, and salt. Gradually stir in cold water until smooth. Cook, stirring constantly, until mixture boils. Boil 1 minute, stirring constantly, then remove from heat.
STEP - 4
In a small bowl, beat egg yolks with a fork. Stir about 1/4 cup of sugar mixture into egg yolks. Gradually stir yolk mixture into remaining sugar mixture in the saucepan. Let cook, stirring constantly, until thick, about 1 minute. Remove from heat.
STEP - 5
Stir in butter, lemon juice, and zest, then pour filling into cooled pie crust.STEP - 6
Make meringue: Reduce oven to 350°. In a large bowl, beat egg whites and cream of tartar until soft peaks form. Add remaining 1/4 cup sugar by the tablespoon until stiff peaks form.STEP - 7
Spoon meringue onto hot filling and spread to edge of crust.
STEP - 8
Bake until meringue is golden, 12 minutes. Cool completely, about 1 hour, then refrigerate until filling is set, 3 hours.