I make this to put over steak, my family really loves it.

Saute mushrooms and onions, in a tablespoon or 2 of olive oil, until onions are almost transparent. Add a couple of tablespoons of brown sugar and cook on high until caramelized. Add a can of french onion soup, 1/4 cup of teriyaki sauces and a splash of Worcestershire sauce. Over low heat reduce until thickened - about 1/2 hour or so.