Pre-bake the pie shell according to package directions.
When cooled, spread the drained pineapple on the bottom of the pie shell.
Preheat the oven to 350. Combine the filling ingredients in the following order, mixing well after each addition: Sugar, flour, cornstarch, salt, reserved pineapple juice, egg yolks, boiling water.
Bring mixture to a boil and boil gently for 3-4 minutes, stirring constantly. The mixture will gel together quickly. Cool for 5 minutes, then add the lemon juice and zest.
Pour the filling evenly over the pineapple within the pie crust.
Beat egg whites and cream of tartar with electric mixer until foamy, about 3-5 minutes. Gradually add sugar, beating until mixture forms stiff peaks. This may take 8-10 minutes.
Spread the meringue over the pie, sealing the edges. Bake for 12-15 minutes or until lightly browned. Cool pie completely before serving.