Beat whites until frothy at #6 speed; add cream of tartar. Beat until stiff enough to hold a point. Beat in sugar gradually at #9 speed. Continue until meringue is stiff and glassy.
Spread in well greased and floured 8 inch pie pan. Bake 20 minutes at 275 degrees. Increase temperature to 300 degrees and continue baking 40 minutes more. Remove to prevent sticking. (Expect meringue to crack more in humid weather.) You can leave meringue in pie pan if it's too difficult to remove. I do.
Prepare filling when meringue is cool: 1/2 c. sugar 3 tbsp. lemon juice 2 tsp. grated lemon rind 8 oz. whipping cream