Frittata with peppers, potato, and salami

There is a particular Italian object you will only ever encounter on a long-distance train at around 12:30, and it is a foil parcel being opened with considerable ceremony by a family of four.

Inside is frittata. It may be between two halves of a bread roll, it may not. There will be a second parcel containing something else. There is very often a bottle of wine that nobody has made any attempt to conceal. And the entire carriage will know precisely what is happening within about eleven seconds, because a frittata being unwrapped is not a subtle event.

The reason it is always a frittata is that no other cooked dish behaves as well away from a kitchen. It needs no reheating. It cannot leak. It is arguably better at room temperature than hot, because the flavours settle as it cools and the salt comes forward. It survives being sat on, which cannot be said for much. And it can be assembled the night before out of whatever is in the house, which historically is exactly what it was.

This version is peppers, potato and salami, which is the one that turns up most often on those trains. The potato is not filler: it is structure, and it gives the frittata enough body to slice cleanly instead of folding over on itself. The peppers go sweet and slightly jammy. The salami renders a little fat that seasons everything else, which is why it goes into the pan first rather than being stirred in raw.

The one rule that decides whether a frittata works is heat. Medium, then low, with a lid on. High heat gives you a brown bottom and a raw middle, which is comfortably the most common way this goes wrong.