In mixing bowl, combine EAGLE BRAND®, lemon juice, lemon rind or extract, and egg yolks; stir until mixture thickens. Pour into chilled crumb crust or cooled pastry shell.
Add cream of tartar to egg whites; beat until almost stiff enough to hold a peak. Add sugar gradually, beating until stiff and glossy but not dry. Pile lightly on pie filling.
Bake 325 degrees F. until meringue is lightly browned. Cool.