Musnad Abu Ya'la al-Mawsili 148:82

Abu Bakr ibn Abi Shaybah narrated to us, Abu Usamah and Muhammad ibn Bishr narrated to us, from Zakariya ibn Abi Za'idah, from Sa'id ibn Abi Burdah, from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah is pleased with the servant who eats a morsel of food or drinks a drink, and then praises Him for it."