Said to have been cultivated in 16th-century Belgium, Brussels sprouts are a member of the cabbage family and, indeed, resemble tiny cabbage heads. Many rows of sprouts grow on a single long stalk. They range from 1 to 1 1/2 inches in diameter; the smaller sprouts are more tender. Brussels sprouts are available from late August through March. Buy small bright green sprouts with compact heads. Store unwashed sprouts in an airtight plastic bag in the refrigerator up to 3 days; longer than that and sprouts will develop a strong flavor. Brussels sprouts, a cruciferous vegetable, are high in vitamins A and C, and are a fair source of iron.