Peanut butter invention turns out to be a bit controversial. Seems that neither John Harvey Kellogg or George Washington Carver invented it. All is revealed by patents and their dates. But there is a little racial ugliness involved which you can read about here.
Here is a riff on inventions and origins of various foodstuffs. No one is going to learn a damn thing if we keep looking for so-called "the origin" of various dishes. Cookery evolves, dishes change slowly over time. The question needs to be about development, further extension of certain ideas. Food and cookery is very like genealogy, as as you know people are not invented, but rather they descend. Rarely, if ever does something spring forth fresh new, unprecedented.
It is also incorrect to claim or assign a certain cookery method to any one group out of the context of all the rest of humankind and all you are going to do is get into trouble if you try to do that. The more I look, the longer I do this work, the more I realize that what all groups and regions have in common is greater than what distinguishes them from each other, and that holds true over time.
Give up the invention stuff. Give up the origin struggle. It is the wrong question, in the wrong place, at the wrong time. Look for what we all have in common and go from there. The bugbear here is ownership of an idea. So forget effective food history until everyone stops trying to say "mine, mine."