Futaba Fruits Parlor, located on the 5th floor of Shinjuku Marui Department Store, is a spacious cafe primarily focused on fruit desserts. It's an omni restaurant with vegan options. The vegan options are marked with a "Happy Vegan" icon.
For the parfait, you'll need to veganise it by swapping the ice cream to a vegan soy ice cream. They also have some vegan savoury options like curry rice.
