Place the fresh Brussels sprouts, celery, carrot, onion, garlic, mustard, thyme, pepper, and salt in a medium pot. Pour broth and cider and stir to combine.
Place pot over medium-high heat, and bring to a boil. Simmer for about 10-15 minutes or until vegetables are cooked through and soft.
Use an immersion blender to blend everything to desired consistency.
Stir in cream and cook another few minutes until slightly thickened.
SNAPPY TIPS: If you don't have an immersion blender you can put the soup in a blender. BUT make sure the soup is cooled or you leave part of the blender top off to let the steam get out. SNAPPY SUBSTITUTIONS: The apple cider and mustard are optional. Use your favorite herb instead of the dried thyme if desired. The seasoning and salt/pepper may need to be adjusted to your family's personal preference.