Heat the oil in a large saucepan and fry the onions and garlic until the onions just start to turn brown around the edges.
Add the rest of the ingredients.
Bring to the boil, then reduce the heat and simmer for 2 -3 hours on low. Keep lid lying loosely on top.
Stir every know and then, especially during the last hour of the cooking process but be careful as the sauce could bubble up and spit up at you. Not a very polite sauce!!
The high sugar content in the recipe (which you need for a good chutney) may cause the sauce to catch quite easily at the bottom of the pot, so, please keep and eye on it. It's really worth the effort.
As it starts to darken in colour, keep stirring, then remove from the heat.
It's difficult to give an exact cooking time as liquids evaporate quicker or slower depending on the size of the pot used, but do it on a day when you're going to be in the kitchen for a few hours.
When cool, remove cinnamon stick and place chutney into sterilized glass jars with secure lids.