sweet potato mallow. 1 pound sweet potato,1/2 cup sour cream, 1/2 teaspoon salt, 1/4 teaspoon ground mace, 1 egg yolk,3/4 cup mini marshmellows...prepare and cook potato. beat sweet potato and sour cream and salt mace and egg yolk on medium speed until smooth.pour in baking dish top with marshmellows bake 350 for about 30 minutes bake uncovered.