In food processor bowl with metal blade or blender container, combine all ingredients except mint leaves; process until smooth. Pour into nonmetal freezer container. Cover; freeze 4 to 5 hours or until almost firm, stirring occasionally.
Line 12 muffin cups with foil baking cups. Spoon mixture into foil cups. Freeze at least 1 hour or until firm.
To serve, let stand at room temperature for 15 to 20 minutes. Garnish with mint leaves.