Combine all ingredients in large saucepan. Bring to a boil, stirring until all dissolved, then boil without stirring until the mixture is dark golden. Test by spooning a few drops into a cup of cold water. The toffee is done when it hardens at once into a crisp ball. Take off heat and pour into a flat oiled pan to make a layer about 1/2 inch thick. When toffee is tepid, score into squares, and when cool break with a hammer and store in an airtight container. Makes about 1.5 pounds.
