Sahih Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Volume: 005 / Book Number: 059 / Hadith Number: 532
Narrated Al-Bara and 'Abdullah bin Abl Aufa:
That when they were in the company of the Prophet, they got some donkeys which they (slaughtered and) cooked. Then the announcer of the Prophet said, "Turn the cooking pots upside down (i.e. throw out the meat)."