In a saucepan mix sliced onion, sugar and demerara sugar.
Now put the pan on high heat and simmer for 1 minute, stirring constantly.
Add ¼ cup (50 ml) of water and bring to a boil.
Add the vinegar and cook for 15 minutes.
Add the thyme and cook for 4-5 minutes
Spoon the hot chutney into sterilized jars, and seal the red onion chutney and it will keep for up to 12 months. Or let it cool and serve with cheese, toast, meat or salad.
Notes
If the onion chutney is too sweet, add more vinegar. You can also use balsamic vinegar but then the ready onion chutney will be browener, it will lose its rubin colour.