Balsamic onion marmalade

Photographer: Adam

This is another of our former colleague Karen’s fail-safe recipes.  Later in the week we will be posting her delicious onion and goats’ cheese tart recipe made with this marmalade, but in the meantime this makes a great pantry staple.

“Onions are always a great store cupboard staple and they’re especially good around harvest time in the late summer.  I make this marmalade with milder red onions when they’re readily available and a bit cheaper and use brown onions at other times.  They both have high sugar content and long, slow cooking caramelises these sugars to give a soft sweet relish that is perfectly offset by the balsamic vinegar and thyme.”


25g butter
1kg onions, very finely sliced
100ml balsamic vinegar
50g dark muscovado sugar
Salt and freshly ground black pepper
Stem of fresh thyme


1. Melt the butter in a large, heavy-based frying pan. Add the onions, salt, pepper and thyme and cook gently for about 30 mins until the onions are soft and transparent but not browned, stirring occasionally.
2. Add the sugar and balsamic vinegar and continue cooking for another 30 mins or so until the onions are almost dry. Don’t rush this stage; the longer and slower the cooking, the better the marmalade will be. Remove the thyme.
3. Onion marmalade can be used immediately or stored in clean sterile jars in the fridge for up to a month. If storing, spoon the hot, or completely cold mixture, into the jars, cover with a disc of waxed paper and seal. Once opened, store the relish in the fridge and use within a week. Serve with cheese, meat and vegetables or use as the basis for bruschetta or a quick and easy tart with feta or goats’ cheese.