This is an easy boil-and-blend recipe from chef Shea Gallante of Ciano. Use it with his Lobster and Shiitake Ragu.
Place all ingredients in a medium saucepan; bring to a boil over medium-high heat and cook until celery root is tender, about 15 minutes. Transfer celery root and cooking liquid to the jar of a blender; carefully puree until smooth. Keep warm until ready to serve.