Follow the recipe for Oven-Charred Broccoli; while the broccoli is roasting, in the same bowl used to toss the broccoli with oil and seasonings, whisk together 3 tablespoons neutral oil, 2 or 3 Fresno or serrano chilies (stemmed, seeded and thinly sliced), 2 medium shallots (halved and thinly sliced), 3 tablespoons lime juice, 3 tablespoons fish sauce and 2 teaspoons packed brown sugar. As soon as the broccoli is done, scrape it into the bowl and toss to combine. Taste and season with kosher salt and black pepper. Transfer to a serving dish and sprinkle with chopped fresh cilantro (optional).