Onion and Pepper Balsamic Marmalade

OK, so this isn't a quick recipe for a 30 minute supper, but it is nice to do at the weekend and it keeps well in a sterilised jar for a week or so in the fridge.  Great to spoon next to bangers, chops,  cheese on toast, with soft goats cheese and a crusty baguette and with courgette fritters - my favourite.  The list is endless.  To make a standard jam jarful, you need 2 or 3 large onions (I like red onions but ordinary ones will do), peeled and sliced, a large red pepper, seeded and cut into strips a little smaller than the onion, a clove of garlic, crushed.  Heat a tablespoon of olive oil in a heavy pan and add the prepped veg.  Stir well, turn the heat to low, cover, and leave to cook for 30 minutes, stirring every now and then.  The volume will decrease dramatically.  Now, stir in a dessertspoon of brown sugar and a dessertspoon of balsamic vinegar.  Add some salt and pepper, tasting and adjusting all of these ingredients until you get the balance between sweet and sour that you like.  Stir well, cover the pot and cook for a further 15 minutes or so until all is jammy and caramelised.  Take the lid off, turn the heat up and stir constantly for another minute or so to drive off any remaining liquid.  Either use straight away or pot into your washed and sterilised jam jar and use for up to a week later.  Because this doesn't contain large amounts of sugar, it isn't a preserve, do it won't last for ever!  You can vary the flavours by changing the vinegar you use (Sherry vinegar is good) and the sugar.  I also sometimes add black mustard seeds or chilli flakes depending on what it is accompanying.  PS: to sterilise a jam jar.  Simple if you have a dishwasher - for those of us without, wash in hot soapy water (inc the lid) rinse in really hot water, then put on a baking sheet in an oven set to 150C for 10 minutes.