🤨 I suppose it started out with Byakuren's own menus, and the others were added in later. Byakuren doesn't eat meat, likely from her Mahayana tradition...

Huh. The vegetarian thing seems to be mostly Mahayana. Vajrayana (Tibetan) permits eating meat, though it's more on the practical side since vegetables are kinda hard to come by in the mountains. Theravada also allows meat consumption, referencing to how the Buddha allowed monks to consume alms that had meat – as long as the animals weren't killed specifically to be those alms.

Ryōtei is basically a high-end traditional Japanese restaurant. And the Keiki menu there is a reference to her signature phrase.