Preheat oven to 425°F.

Cut cauliflower into 1-inch flourets (about 10 cups). In a large baking pan toss cauliflower, garlic, and shallots with oil to coat and roast in middle of oven about 30 minutes, or until golden. In a 4-quart kettle simmer broth, water, roasted cauliflower mixture, and herbs 30 minutes, or until cauliflower is very tender.

Discard bay leaf and in a blender puree soup in batches until smooth (use caution when blending hot liquids), transferring to a bowl. Return soup to kettle and stir in cream and salt and pepper to taste.

Heat soup over moderate heat until just heated through and serve.