“Stuff green onion into the duck body cavity, cover the duck well and braise it at high heat. Xu’s store at Shuixi gate does this dish very well. This is a dish that cannot be made at home. There are yellow and black variations of this braised duck, of the two the yellow one is better.”
Certain sites online says that this duck recipe is actually the predecessor of the modern “Peking duck”, with the yellow version mentioned being salt water duck (滷水鴨) and the darker version being soy-braised and roasted. Sadly the connection between the previous duck dish and the famous roasted one in Beijing is rather hand-wavy.
Nevertheless the recipe does provide one hint that this might be a roasted duck. In Chinese cuisine, when something can’t be made at home it is usually because the home kitchen does not have the specialized equipment or facilities. Then as now, these are usually ovens and grills, so maybe… *waves arms vigorously*