Found the last 3 red onions from the early summer crop lurking in the veg basket. Not having all the ingredients for red onion marmalade recommended on the web I made a similar and tasty dish to my own liking and what was in the cupboard.
Using butter and olive oil I saute'd the sliced onions until soft then used red wine vinegar and some nice stock to make a nice rich sauce. Added two big tablespoons of brown caster sugar to sweeten. A sprig of thyme to add flavour and a little flour to thicken.
This proved very tasty and accompanied various meals for two or three days - especially nice with macaroni cheese.
No picture as we ate it all!