A hadith like this has been reported on the authority of Ka'b b. Malik through another chain of transmitters.
Sahih Muslim Book 36, Hadith 173
← Previous Hadith 'Abdullah b. Ka'b reported that his father Ka'b narrated to him that Allah's Messenger (ﷺ) used to eat with three fingers and when he had finished (eating), he licked them.

Sahih Muslim Book 36, Hadith 172 Next Hadith → You do not know in what portion the blessing lies."

Sahih Muslim Book 36, Hadith 174