Rinse sprouts under cold water. Peel off yellow or damaged outer leaves and trim the stem ends. Halve each sprout lengthwise through the core — the flat cut side browns and caramelizes. Quarter any very large sprouts so everything cooks evenly. Pat thoroughly dry with a kitchen towel or paper towels; moisture steams instead of roasts. Toss in a large bowl with enough olive oil to lightly coat, then season generously with kosher salt and black pepper.

Preheat oven to 425°F, rack in upper third. Line a rimmed baking sheet with parchment or foil. For extra caramelization, preheat the empty pan in the oven. Spread seasoned sprouts cut side down in a single layer — don't crowd the pan; use two pans if needed. Roast at 425°F for 20–30 minutes. Check at 15 minutes. Done when cut sides are deep golden brown and outer leaves are crispy.

Done when fork-tender through the center with deeply browned cut sides and slightly crispy outer leaves — not just lightly golden. If pale or soft, roast another 3–5 minutes. Serve immediately; they lose crispiness as they sit. Finish with lemon juice, Parmesan, or balsamic glaze. Avoid crowding the pan or using low heat — both cause steaming instead of roasting, producing soft, sulfurous sprouts.