Swiss chard is a relative of the beet which has big, tender leaves and crunchy stalks. The taste depends on which part you eat, though not so much on which colour. The large, firm leaves are mild, sweet, earthy and just slightly bitter. The stalks (which can be white, yellow, red, purple, pink, striped and so on) resemble flat celery with a sweet taste slightly reminiscent of beets. Use the leaves as you would spinach, and use the stalks as you would asparagus!