Preheat the oven to 400°F. In a large bowl, toss the Brussels sprouts with 3 tablespoons of the olive oil and season with salt and pepper.
Spread onto a rimmed baking sheet. Roast 20 minutes.
Add the scallions and drizzle with the remaining 1 tablespoon olive oil.
Toss on the baking sheet to mix the scallions with the Brussels sprouts.
Roast until the sprouts and scallions are browned and tender, about 20 minutes more, rotating and shaking the pan once or twice more to make sure all is browning evenly.
Transfer to a platter, squeeze the lemon over the vegetables, and serve.
Excerpted from the book Farmhouse Rules by Nancy Fuller. Copyright © 2015 by Fuller Farm, LLC. Reprinted by permission of Grand Central Life & Style. All rights reserved.