Musnad Ahmad 32:1356

Abu Ja'far al-Mada'ini narrated to us, 'Abbad ibn al-'Awwam narrated to us, from Humayd al-Tawil, from Anas ibn Malik, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, used to like the *thufal* (sediment/dregs)." 'Abbad said: Meaning, the sediment of the broth.