I have been looking for authentic Belgian waffles for years and now I can find them in Harvard square. For those who are looking for the real Liege waffle aka Sugar waffles , Zinneken's is the place to be. For those who don't know, the Liege waffle is a yeast dough filled with pearl sugar (which creates a caramelized coat on the outside) and which is eaten plain, warm or cold as a snack in Belgium. So be aware that these waffles will be different from what people here erroneously call "Belgian waffles."
Some other shops in Boston have tried to introduce the Liege waffle but they are just giving a very fuzzy idea of what a real Liege waffle is supposed to be. If you are looking for the real deal then you should try Zinneken's because they make it with the authentic recipe.