Wash the brussels sprouts well. Trim the stem ends and cut in half from stem to top (quarter, if using larger sprouts) and place in a bowl with the olive oil. Toss to coat the sprouts with the oil.

Make the oregano oil by pulsing the olive oil, oregano, parsley, garlic, and salt in a food processor until the herbs are just little flecks of green. Season with more salt if needed, and set aside.

Heat 1 tablespoon of olive oil in your largest skillet over medium heat. Don't overheat the skillet, or the outsides of the brussels sprouts will cook too quickly. Place the sprouts in the pan flat side down (single-layer), sprinkle with a couple pinches of salt, cover, and cook for roughly 6 minutes; until the sprouts start to caramelize. 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 sprouts are tender and brown on the flat sides, uncover, turn up the heat, and cook a few minutes more, turning with a spatula to get some browning on the rounded side. Remove from heat and just before serving, toss with as much (or little) oregano oil as you like.