- Fill a large saucepan with water and bring to a boil. Immerse cabbage in the water and allow to boil for 5 minutes, or until the leaves are slightly tender. Drain and immediately plunge into cold water. Remove 8 large leaves and set aside.
- Heat oil over medium-high heat in a large saucepan. Add onion and sauté for 2 minutes. Add celery seeds and continue sautéing for 1 minute. Add broccoli, cauliflower, arugula and 750 mL (3 cups) chicken stock. Bring to a boil; cover, reduce heat to medium-low and allow to simmer for about 15 minutes, or until vegetables are tender. Using a mixer or food processor, purée the vegetable mixture. Season with pepper to taste. Reserve.
- In a small bowl, blend mustard, cream and dill. Remove the hard centre vein from each cabbage leaf. Place a salmon rectangle on the centre of each leaf. Spread the mustard sauce on the salmon pieces. Fold up each leaf to make a roll, using toothpicks to secure if need be. Place the cabbage packets in a skillet or large saucepan; pour in remaining chicken broth.
- Cover and bring to a boil. Reduce heat to medium-low and allow to simmer for about 15 minutes, or until the fish is opaque.
- Divide the vegetable sauce among 8 shallow bowls. Place the cabbage packets on the sauce and drizzle a thin stream of cream over top, if desired. Serve with carrots and rice vermicelli.
Prepare more of the vegetable coulis than instructed in the recipe and serve the remainder as a starter the next day, or freeze for another occasion.