In the meantime, I thought you might like to ponder this Double-Mix ad from a 1943 edition of the Topeka Daily Capital.
Gelatin? Xanthum Gum? Petroleum Jelly?
Clearly it is something magical, having the ability to double the amount of butter with a little simple cookery. It also, apparently, allows one to have a disembodied, floating head. And hopefully it is something that even today we'd recognize as safe to eat.