Blend the chilies in a blender. (not a fine paste but some small bits are welcome). Use a little bit of water to do so.
In a sauce pan, add the vinegar, water, sugar, garlic cloves, fish sauce, soy sauce.
Turn on the heat and mix all the ingredients. Bring it to a boil.
Reduce the heat and let it simmer til the sugar dissolves and the liquid thickens. It takes abot 10 minutes give or take depending on the size of the sauce pan and the amount of heat. Stir from time to time.
Add the chili paste and continue cooking for further 8 minutes.
Finally, dissolve the cornflour in 4 tbsp of water and make a slurry. Add the slurry to the caramel. The sauce will now thicken.
Turn off the heat and pour into jars.
You need to keep this refrigerated. It stays for 6 months in he refrigerator.
In case you want to keep this completely vegetarian, then do not use the fish sauce and instead use equal quantity of soy sauce.