Heat oven to 500º F.
Pour the oil into a baking pan, add the sweet potato, and toss to coat. Arrange the slices in a single layer and sprinkle with the salt. Roast until softened and browned, about 20 minutes.
Meanwhile, melt the butter in a large skillet over medium-low heat. Add the bread crumbs and toast until golden. Add in the Parmesan, potato slices, and a few grinds of pepper; toss to coat.
Return to the baking pan. Place in oven and bake until the cheese bubbles, about 3 minutes. Add salt to taste.