To make the pastry, combine flour, sugar, and salt in a large bowl. Cut in butter with a pastry cutter or 2 knives (mixture should resemble coarse cornmeal). Sprinkle with just enough ice water, about 3 tbsp., so that dough holds together, then form into a ball, wrap in plastic, and refrigerate for at least 1 hour.
Preheat oven to 375°. Transfer dough to a lightly floured surface, then flatten and roll into a 9'' round. Ease dough into an 8'' tart pan, prick bottom with a fork, cover with aluminum foil, and chill for at least 20 minutes. Fill tart shell with pie weights or dried beans and bake for 15 minutes. Remove weights and aluminum foil and bake for 5 minutes more. Set aside to cool.
To make the filling, beat sugar and eggs together until mixture is pale yellow. Gradually add melted butter, mix well, then stir in lemon juice and zest. Spoon filling into tart shell and bake until crust is golden and filling is set and lightly browned, about 25 minutes. Cool completely before serving.