Don’t crowd the pan—use two baking sheets for a larger batch so the sprouts crisp properly. Leftovers: Refrigerate airtight up to 4 days. Re-crisp on a baking sheet at 350°F (177°C) for about 5 minutes or in an air fryer for 2–3 minutes. The loose outer leaves roast into extra-crispy “sprout chips”—leave them on the pan!