For 2-3 servings: 1 celery root 1 onion 3 tablespoons tomato puree 1 tablespoon oil salt and pepper seitan (optional) Peel, wash and cut the celery in medium size pieces. Stir fry the  finely chopped onion, 1-2 minutes, in oil.  Add  the celery and cover with water. When the celery is almost cooked add the seitan (optional), tomato puree, salt and pepper to taste. Continue cooking until the celery is done. Variation: You can add olives along with the tomato puree.