2 packages (8 ounces each) cream cheese, at room temperature
1/2 cup heavy cream, chilled
Whipped cream for garnish (optional)
Lime slices for garnish (optional)
To prepare the crust, stir the crumbs, sugar and melted butter in a medium-size bowl. Press the mixture over the bottom and up the sides of a 9-inch springform pan.
To prepare the filling, combine the lime juice and water in a small saucepan; sprinkle the gelatin over the top. Let the mixture stand for 5 minutes to soften. Stir the sugar, eggs and lime rind into the pan. Cook, stirring, over medium heat until almost boiling, about 7 minutes or until an instant-read thermometer registers 160 degrees F.; do not boil. Remove from the heat.
Beat the butter and cream cheese in a large bowl until well mixed, about 1 minute. Gradually beat in the lime mixture until well blended. Refrigerate, stirring occasionally, until the mixture thickens enough to mound slightly when dropped from a spoon, about 45 minutes.
Beat the chilled cream in a small chilled bowl until stiff peaks form. Fold into the lime mixture. Pour into a prepared crust. Cover; refrigerate until firm, 3 to 4 hours.
Run a thin knife around inside of the pan to the loosen sides; remove the sides of the pan. Garnish with whipped cream and lime slices if desired. Store in the refrigerator.
Note: For authentic Key lime flavor, use Key limes, which are more aromatic and citrusy than the commonly available, larger Persian limes.