Peel small sweet potatoes (to avoid a greenish cast, buy mature sweet potatoes); rub with oil. Place on a lightly greased baking sheet. Bake at 350° for 45 minutes or until tender; cool completely. Carefully scoop out pulp, leaving 1/4-inch-thick shells intact.
Mash together pulp with butter, brown sugar, cinnamon, and nutmeg to taste; spoon mixture evenly into shells. Bake, covered, at 350° for 20 minutes or until thoroughly heated. Uncover and top potatoes evenly with Buttercrunch Topping and miniature marshmallows; bake, uncovered, 10 more minutes.