Heat butter in a large pot over medium heat, and add carrots, celery, and onion
Sautee for about 3 minutes, until vegetables have begun to soften
Stir in mushrooms and cook an additional 1-2 minutes
Stir in garlic and cook an additional 30 seconds
Add rice, chicken broth, salt and pepper, and worcestershire sauce, and stir together
Add sage and thyme on top
Cover and heat to simmering. Simmer for 35 minutes, until rice is tender
Remove lid from pot, and remove sage and thyme
Stir in half and half, (optional: dissolve 1 tablespoon of cornstarch into half and half before adding to hot soup to thicken)
Serve as desired with garnishes such as extra mushrooms, parsley, thyme, parmesan