Clean and dry sweet potatoes and peel, if so desired. Cut sweet potatoes into large chunks and place onto a rimmed sheet pan. Drizzle potatoes with olive oil and sprinkle with salt and black pepper. Toss potatoes to make sure well coated with oil, salt and pepper and place into the preheated oven to bake until fork tender, about 20 to 25 minutes. Remove from oven and serve.