I'm fond of Rowans, but most folks find them incredibly bitter.
That said, they are like Elders, every tree is slightly different.
I make Apple and Rowan jelly, it's traditionally used with meats like venison, goose and duck.
We just use it like marmalade tbh.
Some of the Rowan recipes posted on the forum I find too bitter. Traditionally we don't use nearly as much a weight of Rowans to Apples.
Here's the recipe I posted on a thread a while back, and the links to a couple of threads with good information on Rowans too.
Rowan Jelly:
Per kilo (about 2lbs) of apples add one large spray of rowan berries.
Wash fruit and leave wet. Cut apples into quarters or eighths, strip the rowans off their stalks and add to the apples in either a jelly pan or a big pot. Just cover, and no more, with water and slowly simmer the whole thing until the fruit is mushy.
Strain.
This really matters if you want jewel like clarity in your jelly. Strain thoroughly through a jelly bag or layers of muslin. Allow to hang until the juice stops dripping. Do not squeeze.
If you don't mind cloudy, just strain through a fine sieve.
To the juice add in proportion, 1ltr of juice needs a little less than a kg of sugar, and it can manage with quite a lot less if needed, say 800g. That's a pint to a pound for the imperialists.
Add sugar to juice in a jelly pan or heavy bottomed large pot and bring slowly up to the boil stirring to make sure the sugar dissolves. Then, stirring continuously, bring up to a gentle rolling boil for about ten minutes.. Remove any scimmings which form. Drop a little of the jelly on a cold plate to see if it's ready to set. Once the setting point has been reached, remove the pan from the heat and allow it to sit for a few minutes. Then pour into heated, sterilised jars and seal.
More rowans can be added if you really like bitter, but too many make a jelly that overpowers everything else.
http://www.bushcraftuk.com/forum/showthread.php?t=42996
http://www.bushcraftuk.com/forum/showthread.php?t=25065
cheers,
Toddy