Heat oil in a large nonstick skillet over medium heat. Add onion; sauté 5 minutes or until tender. Add water and next 4 ingredients (water through lemon); bring to a boil. Reduce heat; simmer 10 minutes.
Place parsley and next 4 ingredients (parsley through cloves) in a food processor; process until smooth. Add parsley mixture to pan; stir well. Add potatoes; simmer 20 minutes or until almost tender. Add cod and peas; simmer 10 minutes or until fish flakes easily when tested with a fork. Break up fish into bite-size pieces. Remove lemon; sprinkle with pepper and salt. Ladle into soup bowls.