Line a baking sheet with foil or clean brown paper that's been lightly greased. Set aside.
For meringue, in a medium bowl, combine egg whites, cream of tartar, and salt. Beat the mixture with an electric mixer on high speed until soft peaks form (tips curl). Gradually add the 1 cup sugar, beating for 10 to 15 minutes or until very stiff peaks form (tips stand straight).
Drop meringue by spoonfuls onto prepared baking sheet to form 6 mounds. With the back of the spoon, make a depression in each mound, forming a shell.
Bake in a 300 degree F oven for 40 minutes. Turn oven off and allow meringues to dry for at least 1 hour. (Don't open the oven while meringues dry.)
Meanwhile, in a small heavy saucepan, combine egg yolks, the 1/4 cup sugar, lime peel, and the lime juice. Cook and stir over medium-low heat until mixture is just bubbly. Remove from heat. Cover surface with clear plastic wrap and cool, then chill (mixture will thicken).
Whip cream until soft peaks form (tips curl). Stir lime mixture to soften slightly. Fold a small amount of the whipped cream into lime mixture, then fold lime mixture into remaining whipped cream. For some color, tint mixture light green with food coloring. Pile mixture into meringue shells. Cover loosely and chill in the refrigerator for up to 6 hours.
To serve, top each dessert with fresh berries. Makes 6 servings.