How is your spoken Mandarin?
The restaurant is right around the corner from the hotel in the Hua Shan market building, but be prepared for a long wait especially on weekends. The place is called Fu Hang Dou Jiang (阜杭豆漿), and is considered the best in the city - although you'd probably only know the difference if you'd had this food multiple times and have a baseline to compare - I usually eat this type of food in Hacienda Heights CA and there is no comparison.
You can ask the Sheraton concierge to write down some menu items to try, but if you can get these on paper from my post, try some of the following:
Fried egg crepe (like a very thin omelet) 蛋餅
A fried donut inside sesame bread 燒餅油條
Soy Milk (part of the restaurant's name, see the last 2 Chinese characters in the name above) 豆漿
Sweet Soy Milk 甜豆浆
Sticky rice 飯糰
You can ask the concierge to prepare a written order sheet for you and just hand it to the counter for your order...I would also ask for some fried taro cake, and instead of the sweet soy milk, get the peanut soy milk, which is very thick, almost like a peanut milkshake.
This is carbohydrate class 101, so hopefully you'll be doing a lot of walking around after breakfast.