Combine cranberries, sugar, corn syrup, and salt in a heavy, large saucepan; bring to a boil. Heat to 245 degrees F (118 degrees C) or until a small amount of syrup dropped into cold water forms a soft ball that flattens when removed from the water and placed on a flat surface, 20 to 30 minutes.
Gradually stir cream and butter into cranberry mixture, keeping the boil steady. Cook until 245 degrees F (118 degrees C) is reached again, 5 to 10 minutes. Pour mixture into the prepared loaf pan. Cool caramel in pan on a wire rack, about 1 hour. Remove caramel from pan, cut, and wrap individually or serve from pan.
