My pick would be Gascogne. I love French cuisine, and the food there is delicious. Charming ambiance, plus, dining in the garden is always a lovely experience.
I'd start my meal with foie gras. For my main course, either magret or rack of lamb. I'd have a cheese course, and for dessert, either profiteroles or clafouti. No wine because I don't drink. The cost would be around $75.
I don't think it's technically Chelsea (maybe across the street from Chelsea), but Crispo. It's well-priced, and the food is reliably good. My favorite dish is the wild mushroom pappardelle, which usually appears as a special. Other good bets are spaghetti and meatballs, spaghetti carbonara, and the bone marrow.