Onion skins are the most nutritious part of the onion. Yup! That's right! Add them to soup stocks to enrich the broth with flavors and nutrients. Strain the skins from the broth with the other ingredients you make the broth from. You can also put the skins in cheese cloth, netted bag or tea ball to enhance a soup. Now I'm saving the onion skins to boost my soups rather than throw them away.
Source: Eating on the Wild Side by Jo Robinson
