Preheat the oven to 400℉. Slice sweet potatoes in half. Place them on a baking tray lined with parchment paper, cut side up. Drizzle with olive oil, season with salt and pepper, then top with parmesan.
Flip the potatoes over so that the cut side is on the parchment. Place in the oven and bake for 30 minutes or until the sweet potato has softened.