PREHEAT oven to 425°F. Roll out half of the pastry and place in 9-inch pie plate. Place cracker crumbs in crust; set aside.

MIX sugar and cream of tartar in medium saucepan. Gradually stir in 1-3/4 cups water until well blended. Bring to boil on high heat. Reduce heat to low; simmer 15 minutes. Add lemon peel and juice; 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 30 to 35 minutes or until crust is crisp and golden. Cool completely.