At last I have a photo to fit the subject. This is a celery knoll. I know most know the celery has a stalk to eat, but there is also the celery knoll. My Swiss mother-in-law always cooked one with her Sunday roast. And then I also used celery for cooking with a meat dish as I found it a good idea, very tasty. You have to peel it and then cut it in pieces, according to the size you need. I never knew this type of celery from England, but in Switzerland you always find them in the vegetable department in the supermarket. It is also the celery that you can grate and mix witth a salad sauce. I often buy celery salad to eat with cold meat, very tasty.

Actually I had this knoll, or root, in my fridge for some time, watiting for the opportumty to cook it. As they are so large you can keep it until used.