Author's note: A hearty and economical alternative to risotto made with Arbori o rice, barley risotto has become a favorite stand-by when I yearn for somethin g simple and filling. Depending on my mood, I stir in blue cheese, which is as sertive in flavor and adds a wonderful creaminess, or Parmesan, which is more d elicate in taste and provides a slight crunch. Grated sharp Cheddar is also ta sty.