Preheat the oven to 400 degrees F. Place the sweet potatoes in a 9x13-inch baking dish and drizzle with maple syrup. Sprinkle the top with the butter cubes, cinnamon and salt. Then cover tightly with foil and bake for 30-40 minutes, until soft and tender.
Meanwhile, place all the ingredients for the oat crumble (minus the pomegranate arils) in a bowl. Use a fork to mash the ingredients into a crumb topping in small loose pieces. Once the sweet potatoes are tender, stir them gently, then sprinkle the top with the oat crumble and place back in the oven.
Bake the sweet potatoes recipe until the top is golden and crisp, about 15 minutes. Then sprinkle with fresh pomegranate arils and serve warm.