Riyad as-Salihin

'Aishah (May Allah be pleased with her) reported: Messenger of Allah (ﷺ) had slaughtered a sheep and distributed major portions of its meat. Then he (ﷺ) asked, "Is there anything left?" She replied, "Nothing, except the shoulder." Thereupon he said, "All of it is left except its shoulder."

[At-Tirmidhi, who classified it as Hadith Sahih].