Sherried mushroom soup

Ingredients

• 2 garlic cloves , minced, or 1 1/2 tsp bottled chopped garlic
• 1 large onion
• olive oil
• 2 250-g pkg sliced button mushrooms , about 4 cups
• 1 tsp dried thyme leaves
• 1/2 tsp salt
• 1/2 tsp freshly ground black pepper
• 284-mL can undiluted chicken or beef broth
• 3 cups water
• 1/2 cup dry sherry