I don't know why this Restaurant is described as hard to find. I often had problems finding specific locations in china, but not with this one.
Minni wrote how to get there coming from Shaanxi History Museum. If you are at the Big Goose Pagoda it goes like this:
The pagoda is located in a temple and around this temple is a park. If you leave this park through the western exit, then the restaurant is to the right on the opposite side of the road.
I added two pictures from the outside of the restaurant, so that it is easier recognized.
The food was very delicious, but a bit spicy. No english spoken, but (a big) english menue with pictures.
Cons: maybe a bit expensive