Smear chicken with pepper, salt and paprika. Line bottom of a wide, shallow pot with about 1 tablespoon of oil and add sliced onions and garlic. Arrange chicken on top of onions and garlic, then add about half a cup of water.

Cook over high heat for about 10 minutes, then reduce to low heat and cook for approximately 30 additional minutes.  Add celery root to the pot, covering the chicken, and cook for another 30–45 minutes.