Place pan in cold water; cool until mixture mounds slightly when dropped from a spoon.

For meringue, whip egg whites until stiff. Add cream of tartar. Add sugar gradually until mixture is very stiff. Now fold meringue into lemon mixture. Pile into cool baked shell. Chill several hours or overnight. Serve with whipped cream.

Tip: Extra fine sugar will give this light and airy pie an even better texture. If you would like a spectacular topping, whip heavy cream with a few tablespoons of sugar and Limoncello.

Serve cold.