Musnad Ahmad 1153:614

Bahz narrated to us, Sulayman ibn al-Mughirah narrated to us, from Humayd, who said: Aisha said: The family of Abu Bakr sent us a sheep’s leg at night. I held it, and the Messenger of Allah (peace and blessings of Allah be upon him) cut it, or she said: The Messenger of Allah (peace and blessings of Allah be upon him) held it, and I cut it. She said—speaking to the one she was narrating this to without a lamp—she said: Aisha said: "A month would pass for the family of Muhammad, and they would not bake bread, nor would they cook a pot." Humayd said: I mentioned this to Safwan ibn Muhriz, and he said: "No, rather every two months."