Peel and slice the red onions with a kitchen machine, or by hand. Slice the two chillies into thin strips.
Add the oil to a non-stick pan and heat up on medium heat. Fry the onions for 20-25 minutes on a low heat until they start to brown . This will make them sticky and sweet.
Add the sugar and chillies. Mix everything and fry for a further 5 minutes. The onions should be caramelised.
Now pour in the red wine vinegar and balsamic vinegar while stirring the mixture.
Leave to simmer for 45 minutes to an hour. Make sure to stir once in a while or the bottom may burn.
Wait for the mixture cools down and then pour it in the prepared and sterilized chutney jars.
Screw the lids on tightly and its best to leave the chutney rest for the 3-4 weeks for the taste to mature.
Notes
Please see the main post on how to sterilize the jars, and how to seal the jars. Refer to the main post on storage instructions.