Step 1 Heat oil in a large pot. Add onions and garlic and cook, stirring occasionally, for about five minutes or until onions are soft and turning clear.
Step 2 Stir in chilli, cumin and oregano and cook for 1-2 more minutes. Add stock and rice. Bring to the boil then reduce heat to a gentle simmer. Cover with a tight- fitting lid and cook for 30 minutes.
Step 3 Stir beans into pot along with enough extra water (if required) to ensure everything is covered. Replace lid and cook for 15-20 more minutes or until rice is very tender (stir occasionally and add a little extra water if looking too dry).
Step 4 Tip about half the soup into a blender or food processor. Process until fairly smooth (you may have to do this in two batches). Stir purée into soup then thin with water (or milk) if desired. Season with salt and pepper.
Step 5 Serve as is or garnish with a dollop of reduced-fat sour cream, croutons, diced tomato and a little chopped coriander.