Despite its unfortunate name, this is definitely not a fast food restaurant. Perhaps they named it to describe its fast and efficient service. From Thamel, cross Kantipath on the top safe crossing and walk down Kantipath. Takes cca 10 minutes. At the bottom you'll come...to another big crossing with an overhead pedestrian bridge. Turn left with the road and continue for a couple of minutes. The New Kantipur Fast Food has a big entrance from the street and boards displaying pictures of various dishes. Most writing is in Nepali but the name is also in English. The building is painted bright blue for about 1 meter up from the ground and is just before the much pricier Kathmandu Kitchen restaurant. Microbuses and safa tempos stop in front of it.
Kantipur is very popular with locals and only an occasional tourist that braves leaving Thamel strays there. They make fabulous roti and naan on premises, serve it piping hot. Food is prepared fresh and one can taste that. Great vegetable and meat dishes are listed in English menu. Many dishes are accompanied by Nepali home made pickles and chutneys, soups are hearty and tasty. At their low prices you can afford to taste a few of them.
The owner/manager and some waiters speak English and are very helpful. It is much better than Nepali food one finds in Thamel. The place is clean and has simple but spotless toilets. I suggest that you brave the short walk from Thamel and try it. I have been a regular for 5 years and it was always good and clean.More