Preheat oven to 425 degrees. Roll out half the pastry and line a 9-inch pie plate. Place cracker crumbs in prepared crust; set aside.

Heat water, sugar and cream of tartar to a boil in saucepan over high heat; simmer for 15 minutes. Add lemon juice and peel; cool. Pour syrup over cracker crumbs. Dot with butter; sprinkle with cinnamon.

Roll out remaining pastry; place over pie. Trim, seal and flute edges. Slit top crust to allow steam to escape. Bake for 30 to 35 minutes or until crust is crisp and golden. Cool completely.