Put all of the ingredients apart from the cornstarch slurry into a large pan. Bring to the boil then turn down to a simmer for 30 minutes
https://cookpad.com/us/recipes/332952-vickys-soy-sauce-substitute
https://cookpad.com/us/recipes/349993-vickys-baked-teriyaki-chicken-gf-df-ef-sf-nf
Meanwhile you'll need to sterilise some jars. To do so wash them in hot soapy water, rinse well then put them in the oven at gas 1 / 140C / 275°F until your sauce is done. This recipe makes enough to fill around 4 x 454g (1 pound) jars
Put the contents of the pan through a blender and puree smooth. Take out a spoonful and let cool a little then taste to see at this point if you need to adjust the flavour to taste. Don't be scared with the chilli flakes - the sauce will be a bit hot freshly made but will mellow as it sits
Return to the pan, mix in the cornstarch slurry and simmer for 3 minutes until thickened and the starch taste is cooked out
Pour into the hot, sterilised jars (fill just 5mm from the top) and seal. Put the jars on a wire rack to cool then store in a dark place
The colour of the finished sauce will depend on the variety of plums you use
Serve as a dipping sauce or accompaniement to duck, chicken, pork, spring rolls etc
