Chinese style plum dipping sauce

6 lb plums
4.4 lb sugar
A little oil
3 onions, chopped
2 - 3 bulbs of garlic, chopped (depending on size) - lots of cloves, anyway!
2 large chillies, chopped
5- 6 "thumbs" of ginger, grated
3 - 4 teaspoons of Chinese 5 spice
1/2 pint vinegar

Combine the plums (stoned) and the sugar and heat in a large pan, stiring until the juices of the plums mix with and dissolve the sugar.
Bring it to a rolling boil, and scoop off any scum.
Then turn the heat down, and cook slowly, reducing the fluid, and letting the fruit & sugar caramelise. (May take 2 - 3 hours!)
In a separate pan, fry the onion, and then after a few minutes, add the chopped garlic, chillies and grated ginger, and Chinese 5 spice.
When the plum mix has reached a consistency that you are happy with ( I was looking for something fairly jam like), add in the fried onion and spices and pour in the vinegar.
Mix up the contents of the pan, and keep on the heat for long enough for the vinegar to be brought up to temperature too.
Pour or ladle into clean, sterile jars!

This is nice to add to stir frys, or for dipping