Place onion, garlic, coriander and chili into Thermomix bowl and chop 2 sec/speed 6. Scrape down sides of bowl.
Add remaining all ingredients into the Thermomix bowl and cook 60 min/80ºC/speed 2. Cool completely.
TO FLAME GRILL YOUR CHILLI;
Place whole chilli on an open gas flame and turn it a few times until it is charred and the flesh is soft. This will not take ages, but nor will it take seconds. When you are happy that it is well charred, place into a glass bowl, cover the bowl with plastic wrap and allow the chilli to sweat. You can leave the blackened skin on to use in the recipe. This will add a lot of flavour to the salsa.