From A Perfect Discovery of Witches by Thomas Ady (London: H. Brome, 1661), page 59:

Another old Woman came into an house at a time when as the Maid was churning of Butter, and having laboured long and could not make her Butter come, the old Woman told the Maid what was woņt to be done when she was a Maid, and also in her Mothers young time, that if it happened their Butter would not come readily, they used a Charm to be said over it, whilst yet it was in beating, and it would come straight ways, and that was this:

Come Butter come, come Butter come, Peter stands at the Gate, waiting for a buttered Cake, come Butter come.

This, said the old Woman, being said three times, will make your Butter come, for it was taught my Mother by a learned Church-man in Queen Maries days, when as Church-men had more cunning, and could teach people many a trick, that our Ministers now a days know not.