Do you like genuine horseradish sauce? By that I don't mean the stuff you get in jars from the supermarket, but instead the real, home-made version. Horseradish (Armoracia rusticana, syn. Cochlearia armoracia) is a perennial plant of the Brassicaceae family, which includes mustard, wasabi, and cabbages.
Horseradish was cultivated in antiquity, and, according to Greek mythology, the Delphic Oracle told Apollo that the horseradish was worth its weight in gold.
The photograph shows horseradish roots. You eat the roots, not the green leaves of the plant. You should be able to buy a root from your local grocer, or if you are lucky enough to have one, a farmer's market.
Here's my recipe to make a classic English horseradish sauce. It goes well with beef, and smoked fish, like eel and mackerel.
Clean and peel a horseradish root. Grate about two heaped tablespoons of the prepared root into a mixing bowl. Add a dollop of English Mustard, a dash of white wine or cider vinegar, salt, pepper, and sugar. Whip up a quarter of a pint of cream, and mix it carefully with the other ingredients.