This incredibly easy recipe from Heidi Swanson, the excellent chef and author of "Super Natural Cooking". Even brussels sprout haters will love this recipe. Try buying smaller sprouts as they cook more evenly.
Gently rub each brussel sprout half with olive oil, keeping it intact (or you can just toss them in a bowl with a glug of olive oil).
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Don’t overheat the skillet, or the outsides of the brussels sprouts will cook too quickly. Place the brussels sprouts in the pan flat side down (single-layer), sprinkle with a couple pinches of salt, cover, and cook for roughly 5 minutes; the bottoms of the sprouts should only show a hint of browning. Cut into or taste one of the sprouts to gauge whether they’re tender throughout. If not, cover and cook for a few more minutes.
Once just tender, uncover, turn up the heat, and cook until the flat sides are deep brown and caramelized. Use a metal spatula to toss them once or twice to get some browning on the rounded side. Season with more salt, a few grinds of pepper, and a dusting of grated cheese. Serve immediately.