A southern staple, collard greens are an excellent source of vitamins A and C and a good source of folate; they are at their peak harvest from January through April. Shop for collard greens that are bright, crisp and intact, then store them in the crisper drawer of the refrigerator. They can lean toward the bitter side, but blanching them quickly in simmering water can help lessen their strength. Cook in a skillet over medium-heat with a little olive oil until just wilted, or steam. The traditional Southern method is to simmer them slowly for a long time with a ham hock – resulting in very soft leaves with little bitterness.