Bring the first three ingredients to a boil and pour mixture over barley, onion and butter in a 1 quart casserole.
Bake at 325F for 1 1/4 hours, adding a little more liquid if necessary.
Remove cover for last 15 minutes.
Sprinkle top with parsley.
Use in place of potatoes with hot baked ham, roast veal or pork.