I really enjoyed this restaurant/cafe. It´s very chill and pretty. The food was pretty good. The couple running it even sell products like vegan meat and ice cream.
I read that people have a hard time finding it. I went with a Japanese friend and it was very close to the subway.
Although I don´t really remember the road, take the Tozai line to Maruyama Koen Mae and ask someone when you get off. It was only a 7-10minutes walk from the Maruyama Koen station, exit 6.
Cons: You might have to ask for directions