We went to a "Shojinryori" restaurant in Akiharabra - Buddhist food not using any animal products and not using certain spices. You can either chose the small version with three different dishes and rice or the large one where you get a small portion of all the dishes they have. We took the large version and it was so yummy! It costs about 1500¥.
Definitely a recommendation!
Japan, 〒101-0022 Tōkyō-to, Chiyoda-ku, Kanda Neribeicho, ８−２