The portions are enormous at Chinatown’s only restaurant serving the foods of the northeastern region of China known as Dongbei, whose proximity to Korea and Russia influences the hearty, cold-weather cuisine. The service is brusque, but you won’t mind after tasting the tender fried mutton with cumin, hearty sauerkraut stew, and slivers of smoked pork ready to be tucked into pockets of fried bread.