Saffron (infused)
With care — Allowed by some hospitals and not others, or allowed only prepared a particular way.
In one line: Steep a pinch in hot stock until the threads soften completely into the liquid.
Saffron is the dried stigma of a crocus, and it is used in quantities smaller than any other seasoning in this book. A pinch is perhaps fifteen threads. Steeped in hot stock for a few minutes they release their colour and scent and soften to almost nothing, and by the time the risotto is finished there is no thread left to find.
That behaviour makes it an easier case than most spices. It is not a powder scattered over a dish or a piece left in the sauce. It is closer to a tea.
The preparation
Warm a ladle of stock, drop the threads in, and leave them for five minutes until the liquid has turned deep orange. Then add the whole lot to the pan. Do not add the threads dry to the rice, where they hydrate unevenly and stay visible.
Where hospitals differ
Saffron is a spice, and the leaflet this book follows lists spices under foods to avoid. Some hospitals allow it, and St George's allows dried spices generally. This book uses it in one recipe, infused rather than scattered, and that recipe says so.
If you have been told to leave it out
A risotto without saffron is a risotto, and butter, Parmesan and a good clear stock are doing most of the work anyway. It will be pale gold rather than orange. See herbs and spices.