In a large saucepan, cook bacon over medium heat until crisp. Using a slotted spoon, remove to paper towels; drain, reserving 2 tablespoons drippings. In the drippings, saute mushrooms and onion until tender, 5-7 minutes. Add garlic; cook 1 minute longer. Stir in cream and broth; bring mixture to a simmer. Gradually stir in cheese until melted.
In a small bowl, combine cornstarch, salt, pepper and water until smooth. Stir into soup. Bring to a boil; cook and stir for 2 minutes or until thickened. Garnish with bacon and if desired, parsley.
