Wasabi

This pungent green horseradish—no relation to Western horseradish—is a traditional condiment for sushi and is used in dipping sauces for noodles. It is available as a paste in tubes or as a powder in small cans. Once you open a tube, you must refrigerate it. To mix the powder, follow the package directions, which usually call for stirring together a small amount of the powder with a small amount of tepid water and letting it sit for a couple of minutes to allow the flavor to bloom. Be careful when you eat wasabi—a little dab packs a powerful punch.