When you have a cold – and who doesn’t have a cold this month? – the best chicken soup is the kind brought to you in bed. Preferably by a loved one. Preferably while you are permitted to whine about your symptoms. If, however, that particular combination of ingredients is unavailable, Barbara Kafka, New York food expert and author of Soup: A Way of Life, recommends the Thai chicken soup at Vong (200 East 54th Street; 486-9592). Like the Thai classic tom kha gai, it’s full of coconut milk and ginger, and will cut through even the most stuffed-up sinuses. (Kafka also notes that if you can’t make it to Vong, the recipe is in her cookbook.) About classic Jewish-style chicken soup, she’s less enthusiastic, darkly saying, “Delis are not what they once were.” She does like the matzo-ball soup Anne Rosenzweig serves at the Lobster Club (24 East 80th Street; 249-6500), though she warns that it contains “the firm kind of matzo balls, not the fluffy kind.” Enjoy, bubeleh.