from lime, finely grate 4 teaspoons peel and squeeze two third cup juice.
In large bowl, whisk together condensed milk, lime peel, and lime juice until blended. Whisk ice cream into condensed milk mixture until evenly blended. Mixture will be the consistency of sour cream.
Pour ice cream mixture into crust. Freeze at least six hours or until firm. If not serving pie the same day, wrap and freeze up to one week.
To serve, let pie stand at room temperature to soften slightly for easier slicing, about 10 minutes.
Meanwhile in a small bowl with mixer at medium speed, beat cream until stiff peaks form. Top each serving of pie with a dollop of whipped cream and sprinkle with lime peel slivers. Makes 10 servings.