Preheat the oven to 350F.
Peel the sweet potatoes and cut into one-inch cubes.
In a large bowl, toss the sweet potato cubes with brown sugar.
Take a tablespoon of the melted butter and brush on the bottom of a shallow baking pan.
Spread the brown sugar coated sweet potato cubes on the buttered pan in a single layer.
Drizzle the remaining melted butter over the sweet potatoes.
Sprinkle the salt and pepper evenly over the sweet potato cubes.
Bake the sweet potatoes at 350F for 20 to 25 minutes or until a fork inserted at the center or a sweet potato cube goes all the way through without resistance.