Heat a heavy-bottomed pot on medium heat; when it is ready, cook the bacon until crispy, turning a couple times. Remove the bacon to cool and leave the fat in the bottom of the pan.
Add the leeks and cook for a few minutes, stirring. Add the garlic and ginger and cook for another couple of minutes. Add the broth, celeriac, apple-cider vinegar and salt and bring to a boil. Turn down to a simmer, cover, and cook for 15 minutes, or until celeriac is soft.
While the soup is cooking, crumble the bacon.
Transfer to a blender and process until desired consistency is reached, adding more bone broth if needed.
Serve with parsley and crumbled bacon on top.
Recipe by Autoimmune Wellness at https://autoimmunewellness.com/celeriac-leek-soup/