Musnad Ahmad 1153:2059

Rawh narrated to us, Hisham narrated to us, from Hisham ibn Urwah, from his father, from Aisha, who said: "By Allah, a month would pass for the family of Muhammad in which we would not bake bread." I said: "O Mother of the Believers, then what did the Messenger of Allah, peace and blessings of Allah be upon him, eat?" She said: "We had neighbors from the Ansar—may Allah reward them with good—who had some milk, and they would gift some of it to the Messenger of Allah, peace and blessings of Allah be upon him."