As Withm pointed out, "receipt" is the older term for what we now call a "recipe." So, Suzieq, I thought you were just choosing to use more traditional language--very cool.

I don't know anything about the etymology of those words, but it may be that they were called receipts because they were received--as in recipes handed down from mothers and grandmothers and shared with neighbors, etc. Not sure how it morphed into recipe. Anybody got an Oxford English Dictionary handy?