The Great Ponsonby Arthotel Feijoa Jelly Cover the skins in a pot, with water. Bring to the boil and simmer about 20mins. Mash the skins a bit when they're soft, about half way through. Strain in a a sieve. Make the jelly with that strained liquid - match with about equal quantities of sugar. When it reaches setting point, pour into jars and cover.