Make Pie Crust: Combine flour, salt, and sugar. Cut in butter until coarse crumbs form. Add ice water until dough forms. Chill for 30 minutes.Prebake Crust: Roll dough into a 9-inch pie dish. Line with parchment, add pie weights, bake at 375°F (190°C) for 15 minutes, remove weights, bake 5 more minutes.Prepare Lemon Filling: Whisk sugar, cornstarch, salt, and water in a saucepan. Add egg yolks, then lemon juice, zest, and butter. Cook until thickened. Pour into prebaked crust.Make Meringue: Beat egg whites until soft peaks form. Gradually add powdered sugar and beat to stiff peaks. Spread over lemon filling, touching edges.Bake Pie: Bake at 350°F (175°C) for 10-12 minutes until golden. Cool to room temperature, refrigerate 2+ hours.Serve: Slice carefully and enjoy chilled. Optional: top with fresh berries or whipped cream.