Flavourings
Matcha (powdered green tea)
With care — Allowed by some hospitals and not others, or allowed only prepared a particular way.

How to prepare it
Use a teaspoon or less, sifted and whisked in fully. It is tea, not a spice.
Where hospitals differ
No leaflet names matcha. The leaflet this book follows allows tea, and matcha is finely ground tea leaf with no residue at these amounts.