A surprising fact that I read recently was that the top export crop of New Brunswick in Easter Canada is fiddleheads, I would have thought it was Salmon or timber. Fiddleheads are the just emerging croziers of the sterile frond of the shuttlecock fern (ostrich fern) Matteucia struthiopteris, they are native to North America, Asia and most of Europe and has naturalised in the UK. Other ferns emerging croziers eaten but the dominant one is the shuttlecock fern. A few emerging croziers are picked from each crown, usually from wild plants and kept in iced water to keep fresh, frozen or vacuum packed to maintain freshness and shipped all over North America to stores and restaurants.
Very vigorous you will soon have a patch of Matteucia struthiopteris as they spread by runners, efforts to remove them once they are established can be quite a trial. They would be a good natural crop to grow in the moisture retentive shady parts of the garden. They need thorough cleaning and properly cooked by steaming or boiling. But could be more widely grown and eaten in moderation in the UK. Further reading is available here.
It would be a couple of years after planting before you could take a crop but they should have built up to quite a colony by then.