Preheat the oven to 425 degrees. Trim the ends of the brussels sprouts, remove any yellow or bruised leaves and cut into quarters. If the sprouts are small, leave them in halves. Toss with olive oil, salt and pepper, then spread on a sheet pan and roast for about 25 minutes, or until nicely browned and crisp.

While the sprouts are cooking, combine the pecorino Romano, lemon zest, thyme and parsley in a large bowl. Use your fingers to mix everything together until well combined, and no lumps remain. When the brussels sprouts are finished roasting, add them to the bowl and quickly toss to coat in the cheese mixture. Transfer to a plate and serve immediately.