I saw the amazing Terracotta Warriors in Xi'an in 2004. I did not have a steamed mutton type of snack, but I had a lovely meal in a restaurant. In English , " snacks " refer to things like potato chips, sweet or savoury biscuits etc " steamed/boiled mutton " is not popular in western countries. Perhaps you are referring to lamb? Mutton comes from an old sheep and its meat is very tough.

名小吃 = local dish; (here: a specialty of Shanxi/Xi'an cuisine) 羊肉泡馍 = mutton and bread soup