Combine all ingredients in 2 qt. heavy saucepan. Stir and cook over medium heat until sugar is dissolved, then reduce heat and cook at a medium boil, stirring as needed to control foaming to avoid sticking as mixture thickens. If sugar crystals form on sides of pan, wipe them off. 

Cook to the hard crack stage (300 degrees). Remove from heat and let stand 1 minute. Meanwhile, butter 2 sheets of aluminum foil and place on 2 baking sheets. Quickly drop teaspoonfuls of butterscotch onto foil, making patties about 1" in diameter. Space them 1/2" apart. If candy thickens so that it will not drop easily, set pan in hot water until it is again workable.