Prepare the Sweet Potatoes

1. Preheat Oven: Preheat your oven to 400°F (200°C). Line a baking dish with parchment paper for easy cleanup.
2. Toss with Oil: In a large bowl, combine the cubed sweet potatoes with olive oil, salt, and black pepper. Toss until well coated.
3. Arrange in Dish: Spread the sweet potatoes evenly in the prepared baking dish.

Make the Topping

1. Combine Topping Ingredients: In a separate bowl, mix together the chopped walnuts, brown sugar, cinnamon, nutmeg, and melted butter until combined.
2. Sprinkle on Potatoes: Evenly sprinkle the walnut mixture over the sweet potatoes.

Bake

1. Bake: Place the baking dish in the preheated oven and bake for 30-35 minutes, or until the sweet potatoes are tender and the walnuts are golden brown. Stir halfway through for even cooking.