Some one in India many years ago - I'm guessing you're not likely to get any closer to an answer than that.
Who invented the Rice idly?
I read that archaeological finds and ancient records indicate that rice was cultivated in India and China as far back as the third millennium B.C.E. The ancient inhabitants of India called it dhanya, or “sustainer of the human race.” It is still an appropriate name because more people live on rice than on any other single food crop. Most of these people live in Asia, where, according to one source, over 600 million people obtain half their daily food calories from rice alone and where over 90 percent of the world’s rice is produced and consumed.
