There are two Tashi Restaurant in Lhasa. Tashi I and Tashi II which can be found in Kirey Hotel. They have a good range of tibetan cusine and a decent range of American food. I would recommend bobis(they look like fried dumplings) which come with seasoned cream cheese and fried vegetables or meat. Tashi has great cheesecakes and probably the best found in Tibet but this is coming from me who is used to eatting instant noodles for 2 weeks. Also, try the milk tea, which is red tea with yak milk and sugar. The butter yak tea is one that that everyone should drink, even though it is an aquired taste.

When I visited Tibet, I met a Tibet University student who took my partner and me out to eat, so we had good food for a fraction of the cost. So look around, and go to restaurants that most foreigners don't go to. Some of these restraunts even have English translation menus. For breakfast, don't even bother going to restraunts. Many shops are abundant, with stuffed buns you can get half a dozen of for $1 USD. And plan on using paper money, as Tibet does not accept coin money. My partner and I also found small comforts in Lhasa like having afternoon tea. There are cookie shops on most of the main streets and also grocery stores. It's interesting and also a great way to mix with the locals. Everything was clean, so we never got sick from the food.