Chop the onion, celery, and mushrooms.

In a large pot, combine the chopped vegetables, garlic, thyme, and stock. Bring to a boil, then reduce heat and simmer until the mushrooms are soft.

Carefully transfer the soup to a food processor or blender and blend until smooth.

Return the soup to the pot and stir in the cream. Heat through gently.

Serve hot with crusty bread.