Boston Cooler

What is a Boston Cooler?
What is a Boston Cooler?
What is a Boston Cooler?
With all the hype surrounding Halo Burger's free Boston Cooler giveaway, I wanted to know more about this tasty treat.  Much to my surprise, it has nothing to do with Boston, Massachusetts whatsoever.  In fact, most people that live in Boston have never heard of it.