High-heat roasting is an excellent treatment for many vegetables, including fresh beans. The heat caramelizes the sugars in the vegetable and makes them sweet and succulent. You'll lose the bright green color of the beans with this technique, but the browned surfaces are delicious! Truffle oil is now widely available in most grocery stores, but you could also use extra-virgin olive oil, or for a different twist, sesame oil.
Position a rack in the middle of the oven and preheat to 475 degrees F.
Place the beans on a rimmed baking sheet and drizzle with the oil. Toss to coat the beans, then sprinkle with salt and pepper. Bake for 12 to 18 minutes, shaking the pan once or twice, until the beans have brown spots, have wrinkled slightly, and are crisp-tender. Remove from the oven and transfer to a platter. Serve hot.