Place onions and shallots on cookie sheet. Sprinkle with olive oil; toss
vegetables to coat lightly with oil. Sprinkle the vegetables with some salt,
sugar and the thyme leaves.
Roast, turning the vegetables occasionally, 45 to 50 minutes, or until they are
lightly golden. Place the vegetables in a soup pan.
Add rice and vegetable stock. Cover pan and cook the soup at a simmer 35
minutes.
Puree the soup. Return the soup to the pan. Stir in the sherry and cook 1 to 2
minutes. Enrich the soup with cream, heat through and serve.