Googling around for other things, I stumbled across this (which has some information from a half page about witches and a few pages of witch NPC class in Dragon #43). The class is by Bill Muhlhausen (revised and edited by Kim Mohan and Tom Moldvay). The small article about witches is by Moldvay.
The Other Side Blog is a game design blog from Timothy S. Brannan
theotherside.timsbrannan.com
View attachment 150696
The powers gained at various levels include: Brew poisons and narcotics, Brew truth drug, Brew love potion, Read Magic-User, Druid & Cleric scorlls, Candle Magic, Acquire familiar, Brew flying ointment, Manufacture control doll, Fascinate, Limited Wish, and Shape Change. There is also a full spell list.