Boston Baked Beans are a candy industry name for sugar coated peanuts that have been dyed red to match the color of, you guessed it, baked beans.
Their origin is muddy. No one really seems to know who came up with them. At one point, there were several purveyors. Today, the lone holdout is the Ferrara Pan Candy Company started by an Italian immigrant who made a home for himself in Chicago. In the "old country," Salvatore Ferrara learned the art of making confetti, or sugared almonds, so it's no wonder they branched out into an all-American nut like the peanut.
Boston baked beans are made using a "cold panned" candy process. Peanuts are mixed in a revolving pan and sugar and other ingredients are slowly added in to coat and cook the candy to perfection. The entire process takes four days to complete and can actually be viewed here.
If the Ferrara Pan Candy sounds familiar, it might be because they make a number of other sweets like Lemonheads, Atomic Fireballs, and Red Hots. Boston Baked Beans are the only confection they still make that contains nuts.
This whole thing got me thinking about other foods that have names that don't match their ingredients. For example, there is no butter in peanut butter, no seafood in Swedish fish, and no eggs in an egg cream. Can you think of any more?