Preparation

• Position a rack in the center of the oven and heat to 425°F.
• On a rimmed baking sheet, toss the green beans with the oil, 1/2 tsp. salt, and 1/4 tsp. pepper, and spread in a single layer. Roast until the bottoms begin to brown, about 15 minutes. Toss, rearrange on the baking sheet, and roast until tender and golden brown in places, about 5 minutes more.
• Toss the beans with the lemon zest, if using, season to taste, and serve.