Butter a 2-quart baking dish. Heat oven to 350 F.
Mix the mashed sweet potatoes with the granulated sugar, milk, 1/2 cup of melted butter, vanilla, and salt. Spoon into the prepared baking dish.
Mix topping ingredients together until well blended. Sprinkle over the potatoes and bake for 30 to 35 minutes.
Calories per serving: 514