The traditional way of sautéeing onions until brown (caramelizing) can destroy many of their health benefits. I discovered that Healthy Sautéeing not only helps bring out their sweet flavor but helps to preserve more of their nutrients. You can also steam sliced onions for 5 minutes. (Taken from page 367 of the 2nd Edition of the World's Healthiest Foods book.)
Slice onions and let them sit for at least 5 minutes.
Heat 5 TBS broth or water over low heat (if your burner is medium output) in a stainless steel skillet, covered. Do not us high output burner.
As soon as broth begins to steam, add onions and cook, covered with a tight fitting lid for 7 minutes. The onions will release a small amount of liquid. Stir onions once broth has evaporated so they won't stick to pan should not be burnt.
Remove from heat when onions become translucent, about 7 minutes, depending on the thickness of the slices. Transfer to a bowl and toss Onions with the remainig ingredients while they are still hot. Research shows that fat-soluble vitamins and carotenoids found in foods, such as Onions, may be better absorbed when consumed with fat-containing foods like extra virgin olive oil. The oil also helps tenderize the Onions.