Musnad Ahmad 1167:47

Hassan narrated to us, he said: Ibn Lahi'ah narrated to us, he said: 'Aqil bin Khalid narrated to us, from Ibn Shihab, from 'Urwah, from Asma' bint Abi Bakr, that when she would prepare *tharid* (a dish of bread and broth), she would cover it for a while until its steam subsided. Then she would say: "I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: 'It is greater for the blessing.'"