From Julia Child's "Mastering the Art of French Cooking". This is a savory mixture of sliced onions, rice and butter cooked slowly together until they melt into a puree. The natural moisture of the onions is sufficient to cook the rice; no other liquid is needed. Soubise is particularly good with veal or chicken. It may be turned into a sauce soubise by pureeing it with a sauce bechamel or veloute and enriching it with cream.