There are at least two bands who go by the name Marshmallow. 1. Marshmallow is Matija Habijanec, an indie-lo-fi-pop singer-songwriter from Krapina, Croatia. Now known as The Marshmallow Notebooks. 2. Marshmallow is a four piece powerpop band based in London, England, fronted by Alan Gregg, formerly the bass player with New Zealand band The Mutton Birds.