Preheat your oven to 400°F (200°C). Lightly grease a baking dish with butter or cooking spray.

Peel the sweet potatoes and cut them into uniform 1-inch cubes.

In a large mixing bowl, combine the cubed sweet potatoes, melted butter, maple syrup, ground cinnamon, and half of the chopped walnuts. Toss gently until coated.

Spread the sweet potato mixture in the prepared baking dish in a single layer. Roast for 25 to 30 minutes until tender and caramelized.

With about 5 minutes left, sprinkle the remaining walnuts on top of the sweet potatoes.

Let the dish cool slightly before serving. Drizzle with more maple syrup if desired.