In a small pot or large saucepan, combine all ingredients except the vanilla and salt. Cook over medium-high heat, stirring occasionally, until the mixture comes to a boil.
Continue cooking without stirring until a candy thermometer reaches 244-250°F, or a small amount of the caramel dribbled into ice water can be squished into a soft ball. Stir in the vanilla and salt and pour into a parchment-lined 8x8-inch pan. Chill until set, and cut into squares. Makes 3-4 dozen pieces.