Chard leaves. As with most greens, preferably picked in the cool of the morning. Pick far more than you think you’ll need, it cooks down big-time.
Start on high heat with an ounce or so of water to prevent it sticking to the bottom of the pot. Once steaming, cover, and let cook slowly over low heat, until completely wilted and dark green. I leave the lid off when done, and cook off any excess liquid. I suppose you could pour it off. Add some good butter, salt and pepper. Toss. Alternatively, good oil, salt and pepper. This is a good place to use extra virgin canola oil, in my opinion. Yes, you heard me right: extra virgin canola oil.