PREPARE a syrup of equal parts of sugar and water. Add a piece of vanilla bean, and bring to a boil, stirring frequently. Reduce the heat and add the pears, first peeled, halved, and cored. Poach them until they are just tender, then remove and let them cool.
Peel and quarter the celery root and cut it into fine julienne strips. Parboil these for 1 minute in rapidly boiling salted water. Drain, season with salt and pepper, and cool. If celery root is not available, substituts finely diced celery hearts.
In a small bowl combine the lemon juice, salad oil, the onions, finely chopped, the minced tarragon, and the cinnamon, salt, and freshly ground pepper. Mix well. Arrange the pears and celery in a glass or china bowl, pour the dressing over them, and serve chilled.
