Celery root soup with parsley oil recipe

It may be knobby and ugly on the outside, but when celery root is cooked, its inner beauty is revealed. This creamy soup has an almost gossamer texture and the delicate flavor of celery root, which has hints of celery and parsley. The parsley oil made by pureeing the herb with olive oil and then straining it underscores that flavor and adds a beautiful swath of green to the pale yellow soup.