Cook garlic in melted butter in large pot over medium heat until golden.
Add cream, chicken stock, salt, mustard, and tarragon. Bring to a boil.
Stir in chopped broccoli and celery. Return to boil. Reduce heat to low and simmer for about 5-10 minutes; stirring occasionally.
Add cheese and stir over medium-low heat until cheese is melted.
Video
Notes
A stick blender can be used to help incorporate the cheese into the soup. It can also be used to puree some of the vegetables.Makes about 8 cups of soup.