Ground root of the Cochlearia armoracia (Armoracia rusticana), a hardy perennial plant of the mustard family. Celebrated pungent flavor released when liquid added. Try 1 tbsp. powder folded into 1/2 c. whipped heavy cream or mix with sour cream for faithful companion to English Roast Beef. Let stand about 30 min. Easy addition to sauces, salads and spreads.