1 small red onion (or red shallot), sliced
Olive oil
1-2 tbsp. fine brown sugar
¼-½ cup dulse, chopped
3-4 tbsp. red balsamic vinegar
Chilli sauce (optional)

This is a really dark coloured variation on the well-known red onion condiment and goes well with robust grilled fish and also fried fish.

When I have produced this it has been for immediate use, so I have no idea what the storage qualities would be like; although properly stored red onion marmalade kept in a fridge may keep for 2 to 3 months. 

For a slightly different spicy alternative, add a few drops of chilli sauce along with the vinegar. Rice vinegar may also be used for a milder version and has less of a vinegary bite.

• Sweat the onion in a little oil over a low heat until the onion softens, stirring from time to time.

• Then add the sugar and continue cooking until the onion juices have evaporated and it starts to caramelise - about 30 to 40 minutes - but stir occasionally to ensure the mixture does not stick to the pan and burn.

• Add the balsamic vinegar and dulse, stir thoroughly, and allow to cook for another 20 to 30 minutes, adding a splash of water if the mixture appears to be drying out.