This delectable condiment is a wonderful method of transforming onions into a sweet package of goodness. Onion jam has a fleeting similarity with caramelised onions, but where caramelised onions rely on long cooking time to transform the onions into sweet goodness, this onion jam has a little help along with sugar, just like regular jam. However, the flavour is decidedly savoury.
The applications for onion jam are pretty wide. The most likely accompaniments are red meat dishes, but they have a strong affinity for all sorts of savoury dishes. They can be used on a sublime vegetarian sandwich of roasted tomatoes, goat's cheese and rocket or as a filling for a savoury tart. Try pairing these onions with a simply grilled chicken breast and a green salad for a delicious mid week meal.
You can make these onions on a Sunday afternoon and store them in the refrigerator for at least a fortnight, so they will be ready to add to your dish at a moment notice, enlivening all that they touch.
Peel the onions, then slice off the top and base. Turn the onions on their side and slice into fine rings. In a large, heavy-based saucepan heat the oil to a medium-high heat. Add the onion slices and saute for a few minutes.
Add the vinegar, sugar and mustard seeds (If using), stir, and lower the heat to the gentlest of simmers. Cook at this heat for around an hour, stirring occasionally. Add a little water if it gets dry. When the onions have become very soft and a deep crimson colour, add the salt and pepper to taste, then remove from the heat. Allow to cool. Store in the refrigerator in an airtight container.