On MEDIUM-HIGH heat melt the butter in the saute pan.Add the red onion and the salt to the pan, and sauté until onions are translucent.Deglaze the pan with the red wine vinegar dressing and brown sugar, then cook until the liquid is gone - about 3-6 minutes.Place in the sealed container and store up to seven days in the refrigerator.Deglaze the pan with the red wine vinegar dressing and brown sugar, then cook until the liquid is gone - about 3-6 minutes.Place in the sealed container and store up to seven days in the refrigerator.