This leafy green looks something like watercress but has a distinctive flavor—nutty, pealike, slightly peppery. I use the young tricolor leaves raw in salads, and when the amaranth is more mature and the leaves have a red tint, I stir-fry them quickly, sometimes in combination with spinach, or braise them with onion, garlic, chicken stock, and cumin. —Floyd Cardoz, chef and author, New York City