Cook the onion in water in a large pan for 5 minutes. Do not brown.
Add the peppers, garlic and potatoes, then cover and cook gently without browning for 5 – 10 minutes.
Add the AVM Broth and simmer 15 – 20 minutes, until the vegetables are very tender.
Puree the soup in a blender or food processor, adjusting the consistency with water if necessary.
Add the lemon juice, a tablespoonful at a time and seaweed to taste.
Chill and garnish with fresh basil.