1. Prepare piecrust mix, or make the pastry from your favorite single-crust recipe. Roll out to a 12-inch round on a lightly floured pastry cloth or board; fit into a 9-inch pie plate. Trim the overhang to 1/2 inch; turn under, flush with the rim; flute to make a stand-up edge.
2. Beat eggs slightly in a medium-size bowl; blend in sugar, salt, corn syrup and vanilla; stir in flour. Pour into prepared shell; arrange pecan halves in pattern on top.
3. Bake in moderate oven (375°) for 45 minutes, or till center is almost set but still soft. (Do not over-bake filling will set as it cools.) Cool the pie on a wire rack.