Difficult one, this one – expensive too. What sort of truffle? In Umbria during summer there is a relatively abundant truffle known to its friends as Tuber aestivum or summer truffle. It is also comparatively inexpensive over there, about £100 a kilo or £2–3 a portion. It freezes well and is normally served raw, grated directly on to food straight from the freezer. Buy some if you get a chance in Italy, wrap them in tissue, put in a jar and refrigerate. Freeze individually, clingfilm wrapped, when you get them home. Use by Christmas.
That’s the truffle sorted out, now the rocket. The correct leaf for this dish is Eruca sativa, wild rocket. In fact this means any small, very strong rocket. I hope by the time this book comes out that supermarkets will sell rocket in realistic quantities and treat it like a salad and not like a herb.