Horseradish is a member of the mustard family and it's the root of the plant that's used in cookery. The root, which is similar in appearance to a parsnip, releases a distinctive aroma when bruised or cut and has a very hot, peppery flavour that is more powerful than mustard. Once peeled, it can be grated and mixed with cream and other ingredients to make a hot-flavoured sauce to accompany roast beef or fish such as trout.
Fresh horseradish is difficult to source. Try a good farmers' market or specialist supplier, or look online.
Keep fresh horseradish in a paper bag in the fridge for up to one week, or cut it into smaller pieces and freeze until required. To prepare fresh horseradish root, just peel it and grate. Grate only the quantity you need, as once peeled it will lose its pungency quite quickly. Use horseradish raw in sauces - cooking destroys its flavour.
Horseradish is traditionally made into a sauce to serve with roast beef, venison or robust-flavoured fish such as tuna, smoked trout and mackerel. It is grated and can either be mixed with cream to make creamed horseradish sauce, or mixed with vegetable oil to give hot horseradish sauce, which has a stronger flavour and a thicker consistency than creamed horseradish. Take care when grating horseradish as the vapours can sting your eyes. Serve with venison or well-flavoured fish such as mackerel or tuna, or stir into mashed potatoes for a tangy flavour.