1kg medium brown onions
2 tblspns olive oil
70g mustard seeds
375ml red wine vinegar
285ml sweet chilli sauce
Peel onions, cut in half and slice thinly.
Place a large heavy-based pot over medium heat, add oil and cook onions until softened. Add sugar and mix until dissolved. Add mustard seeds, vinegar and sweet chilli sauce.
Increase heat to high and cook until reduced and thickened, about 30 minutes.
Pour into sterilised jars, wipe the inside rim with vinegar and seal.
Makes about 6 x 250ml jars.