In a pressure cooker (insta-pot), place onion, beetroot, apples, vinegar, sugar, mustard seeds, ginger, dates, coriander, cloves and cinnamon.
Place lid on and bring to pressure. Cook for 25 mins and turn heat off. Allow to de-pressure naturally.
Take lid off and simmer for a further 20 mins to thicken.
Place in sterilised jars and lid.
***TIP***
I put my jars and lids in the oven in a tray and turn heat to 75. Leave for at least 10 mins at heat and your jars are sterilised and ready to go.
***ALTERNATE COOKING METHOD***
Place in normal pot, bring to soft boil then simmer for 1.5 hours.Follow all other steps.