Step 1:

In a large saucepan, heat the butter and oil over medium-high heat. Stir in the onion, celery, and carrot and saute for 5 minutes, or until tender. Add the flour and cook, stirring constantly, until bubbly. Stir in the stock, tomatoes, wine, bay leaf, marjoram, and nutmeg and bring to a boil. Lower the heat and simmer, covered, for 15 minutes, then discard the bay leaf.

Step 2:

In a food processor or blender, pur?e the soup, in batches if necessary, for 45 seconds, or until smooth. Return the soup to the saucepan. Add the shrimp and cook, uncovered, over medium heat for 1 minute. Blend in the milk and cream and cook 2 minutes longer, or just until the soup is heated through and the shrimp are firm and pink. Remove from the heat and season with the salt and lemon juice. Garnish with sprigs of marjoram.