While it's technically more a cake than a pie, no ode to America's historic desserts would be complete without this cream-filled favourite. Invented at Boston's Parker House (now the Omni Parker House) in the 19th century, a classic Boston cream pie sees a pillowy sponge layered with vanilla custard and topped with chocolate icing. You can still sample this delectable sweet treat at its birthplace and even get it delivered from the hotel to your door.