I prefer pressure cooking collards, but here's how I boil them on the stovetop when I can't find a part to my cooker.
Pick the collard leaves by cutting the stems. Leave the roots and you will get more collards. I cut away any bad parts and remove any insects or insect eggs. I pull out thick, tough stems--I don't like them. I prefer small leaves, a little bigger than my hand, for tenderness and sweetness. Larger leaves, I roll together and then cut into sections which makes strips. I wash them in a large clean sink filled with water. I change the water at least 4 times or until it stays clear. I add them to a pot of boiling water with seasonings already added (salt, piece of ham or ham bone, black pepper, onion, garlic, etc), adding more than the level of the water. They cook down fast. I bring them to a boil and then let them simmer until they are very tender. The time this takes depends upon how many you have and how big (tough) the leaves are. I just sample them until they are done to my liking.
Retain the juice. It is filled with nutrients and will make a good base for soup. It is called "pot likker" and some people like to sop it up in a biscuit.
Collard leaves contain calcium vitamins B1, B2, B9, and C and beta-carotene. It also contains beneficial enzymes.
