Finely slice the red onions, pour a tablespoon of olive oil into a frying pan and fry the onions on a medium heat until they’re soft (but it’s ok if they caramelise a bit – that adds flavour!).
When the onions are soft (about ten minutes of cooking) add the sugar & vinegar and mix then simmer (cook slowly on a medium heat, so it bubbles gently) until its thick and sticky.
Real Junk Food Manchester notes…
In this recipe the sugar and the vinegar can both be replaced with different types. For example, use brown sugar and cider vinegar. This recipe also works well with tomatoes for a savoury alternative, or plums for a sweet one.