A cruciferous family member, Brussels sprouts have long been considered cancer-fighting superstars thanks in part to the presence of compounds called indoles.
Preheat oven to 425 degrees. On two large rimmed baking sheets, toss Brussels sprouts, pears, shallots, thyme, and oil; season with salt and pepper.
Roast until Brussels sprouts are tender and browned, 30 to 35 minutes, rotating pans halfway through. Toss with lemon juice and serve warm.