Spiced plum chutney

I trusted Hugh Fearnley-Whittingstall and his recipe published in The Guardian , but I forgot to buy the apples. I hope you can trust me and mine slightly changed recipe for spiced plum chutney. It tasted good when still hot, but I like quite sour, vinegar taste. It will fully develop it's flavour after 2-3 months maturing.

Due to the lack of apples that contain a lot of pectin, I used liquid pectin (Certo) and changed some quantities.   I am not sure which variety of plums I used, as there was not information on the market and I forgot to ask. I am going to make some more of this chutney later on this summer, with August ad September varieties, such as damsons or similar. 

Makes 6 jars, about 200ml each 

1.1 kg plums, quartered and stoned
300g onions, peeled and diced
180g stoned prunes, roughly chopped
fresh root ginger thumb size, peeled and finely chopped
400g soft dark brown sugar
400ml vinegar (I used some malt and some red wine vinegar)
2 tsp dried chilli flakes
salt
2 tsp mustard seeds
2 tsp black peppercorns, roughly crushed
about 70g of liquid pectin

Place all the above except the pectin in heave based pan. Bring to the boil and then simmer for about 2 hours, stirring occasionally, especially be careful with last 30 minutes, when chutney gets sticky and tends to burn. Then remove from the heat and stir in the pectin.

Place hot chutney in the sterilised jars, seal and turn up side down and leave them to cool down. You can pasteurise it of you wish to keep it for longer than 6-9 months. Our chutney will disappear before end of this year. Allow to mature for about 2-3 months.