Beat egg yolks until lemon colored. Blend in condensed milk slowly. Add cream of tartar to egg whites and beat until foamy. Continue beating, adding sugar (1 T. at a time) until egg whites peak. Fold 6 T. of the meringue into the filling mixture. Pour into 9 inch baked pie shell. Top with meringue and bake at slow oven 330€ until golden brown.