You might try Topaz, a Thai place, on 56th St. between 6th and 7th Avenue (north side of the street.) Walk a few steps down--it's below street level. It's next to the Mystery Bookshop.
I often find Thai recipes too sweet for my taste, but I've had two top-notch lunches recently at this old-favorite, reasonably-priced, very popular--and quick-serving--spot.
I can recommend:
--the hot lemongrass soup--outstanding, concentrated flavor
-- the glass noodles with minced pork salad in lime juice (served at room temperature)
-- grilled barbecued whole shrimp in a spicy hot sauce
-- minced pork in lime juice salad (sans noodles)
--grilled Thai beef--beautifully thin slices of good quality medium-rare beef with a chili sauce on the side that was good enough to dip my lettuce into!!
You get a bowl of those addictive, mutli-colored prawn crackers with hot sauce to keep you going until your meal arrives. Which it will in a VERY short time!!
Hope you enjoy it.