From Sahih Muslim (Hadith 2715):
A'isha, the Mother of the Believers (Allah be pleased with her), reported:The Apostle of Allah (ﷺ) came to me one day and said: Is there anything with you (to eat)? I said: No. Thereupon he said: I shall then be fasting. Then he came to us another day and we said: Messenger of Allah, hais has been offered to us as a gift. Thereupon he said: Show that to me; I had been fasting since morning. He then ate it
Reference: Muslim 2715