Halves of Brussels sprouts look pretty mingled with any variety of chard, and they taste wonderful together, too. Substitute kale, collards, escarole, or broccoli rabe, depending on what’s available.
In a large skillet, combine the Brussels sprouts with about ½ cup water. Cover and cook until tender-crisp, about 5 to 7 minutes. Drain and remove to a bowl and set aside.
Meanwhile, cut the leaves from the chard stems. If using the stems, trim about and inch from the bottoms, then slice thinly. Otherwise, discard them. Stack several leaves atop one another and slice into ribbons, about ½ inch in width.
Heat the oil in the same skillet. Add the garlic, bell pepper, and chard (along with stems if you’re using them). Sauté over medium heat until the chard is tender to your liking, about 4 to 5 minutes.
Stir the Brussels sprouts back in, then season with lemon juice, salt, and pepper. Scatter the optional nuts over the top and serve at once from the skillet.