Bring several cups of water to a boil in a medium-sized stock pot or sauce pan. In a colander or steam basket set over the pot, steam the cabbage leaves until just soft and wilted slightly, about 3-4 minutes, working in two batches if necessary. You want to make sure that your leaves are tender enough that they will bend but not so soft that they will tear when rolled. Transfer the leaves to a paper towel-lined plate.