"Jiffy" is a baking mix, e.g., corn muffins, cake mix. JIF is peanut butter. Apparently Bette hasn't set foot in a grocery store or a kitchen in her life. Or she was thinking of SKIPPY, which is pb, but not of the Jiffy variety.
She can bring all the corn muffins she likes, as long as there's some chili or bean soup to go with it.