1/2 cup bottled Key lime juice (such as Nellie and Joe's)
1/2 cup whipping cream
Dash of salt
1 (14-ounce) can sweetened condensed milk
6 graham crackers (1 1/2 cookie sheets), coarsely crushed, divided
Key lime wedges (optional)
Combine first 5 ingredients, stirring with a whisk. Pour mixture into freezer can of an ice-cream freezer, and freeze according to manufacturer's instructions. Stir 1/3 cup graham crackers into ice cream. Spoon ice cream into a freezer-safe container, and cover and freeze for 1 hour or until firm. Sprinkle each serving with 1 teaspoon graham crackers. Garnish with lime wedges, if desired.