Step #2 Cook until onions start to get transparent.
Step #3 Put that mixture & all the other goodies in a food processor/blender or mixer.
Step #4 Blend until very smooth.
Step #5 It will look like a green milkshake -- THAT IS A GOOD THING
Here is where you make you personal choice -- You can return mixture to pan & let simmer for 30 mins & then put in the fridge OR you can as soon as possible chill in the fridge.
Step #6 I usually chill right away in the interest of time.
Step #7 Either way it is good.
Step #8 If you simmer it the mixture will get thicker, but it is plenty thick enough without doing it.