Over an open flame, roast all peppers. Place in a small container or paper bag and seal. Allow to cool for 10 minutes.
Wearing gloves, remove peppers from bag and peel off skin from peppers (I usually do under running water.) Remove stems and seeds from peppers and roughly chop.
Heat oil in a small stock pot. Add onions and garlic and cook 3-4 minutes, or until fragrant and beginning to turn translucent.
Add peppers, chicken stock, salt, pepper, coriander and cumin. bring to a quick boil then immediately reduce to a simmer. Allow to simmer for 5 minutes.
using an immersion blender or food processor, lightly pulse until a more sauce like consistency is achieved, but leave somewhat "chunky."