For antebellum peanut recipes, look in the Carolina Housewife. Another place to look is in Francis Peyre Porcher's books, Resoources of the Southern Fields and Forests? Something like that--there are several editions, little articles and a whole long book. Anyway, as I recall, he mentioned peanuts beaten up and mixed with sugar eaten as a dessert. Sounds like sweetened peanut butter. They were also used as a coffee substitute as Allie mentioned.
When searching in period books, look for "ground nuts" "groundnuts" "goobers" "pindars" and all those synonyms too, especially ground nuts.
Wilmington was ground zero for the commercial peanut growing business, so it's no surprise there are recipes for peanut foods there. Though most peanuts were eaten roasted like we do. Along with some African imports, Wilmington and other peanuts were shipped all up the east coast and inland for eating at fairs, on railroads, from street corner vendors, at theaters, etc. You'll sometime see the story that Yankee soldiers were first introduced to peanuts during the war and wanted to eat them afterwards when they got home, but pre-war primary sources show anyone who went where people gathered was already familiar with peanuts in the north, at least back to the 1830s.
Don't have time to dredge up the full quotes and citations right now, but that gives an idea for online books and keywords.