Dried beef is combined with mushrooms in an easy cheesy sauce. Pimientos provide color to the dish, but you may leave them out if you prefer. Add some shallots or green onions to the skillet along with the mushrooms, if you like. Feel free to use 12 to 16 ounces of thinly sliced strips of tender beef or leftover sliced pot roast or shredded beef instead of dried beef.