Cod with Vegetables

Name: Cod with Vegetables
Ingredients: 2 bunches Soup vegetables (carrot, leek, parsnip) (such as carrot, leek, parsnip or other aromatic vegetables such as celery or onion); 1 Onion; 1 jar Fish stock (400 ml); 250 milliliters dry White wine; 2 Bay leaves; 4 Allspice berries; 4 Peppercorns; Salt; 1 kilogram Cod (or cod, ready to cook); 1 tablespoon Butter; 2 teaspoons Pastry flour; 4 teaspoons grainy Mustard; 2 tablespoons Creme fraiche cheese; white freshly ground pepper; 1 pinch Sugar; 2 tablespoons Chopped green onion